MQTT Connection Status -22

[azwawe]

Hi. I am trying to develop a project that use mqtt connection using nrf9160. Currently using thingy:91 for evalutation board. I am using Mobily Network on NB IoT at Saudi Arabia. Now I manage to connect to NB-IoT Network but when it is trying to connect to mqtt connection, I got message that the connection status -22.

I am trying to find a solution that provide information about that error but I can't find anything about that. Please let me know if there is any information that I can check on the code or configuration. Thanks 

[Einarh]

Hello!

Error 22 means "invalid argument":

https://github.com/nrfconnect/sdk-nrfxlib/blob/main/nrf_modem/include/nrf_errno.h

I would recommend checking the inputs you're giving to the function that returns this error.

Best regards,

Einar

[azwawe]

Thanks for your fast response.

The input is only a client object. 

#include <zephyr.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zephyr/kernel.h>
#include <nrf_modem_at.h>
#include <modem/lte_lc.h>
#include <modem/location.h>
#include <date_time.h>
#include <zephyr/drivers/uart.h>
#include <sys/printk.h>
#include <usb/usb_device.h>
#include <drivers/uart.h>
#include <string.h>
#include <zephyr/net/mqtt.h>
#include <zephyr/net/socket.h>
#include <zephyr/random/rand32.h>

#if defined(CONFIG_NRF_MODEM_LIB)
#include <nrf_modem_at.h>
#endif

#include <modem/lte_lc.h>
#include <zephyr/logging/log.h>

/* Check which one is the modem */
#if defined(CONFIG_MODEM_KEY_MGMT)
#include <modem/modem_key_mgmt.h>
#endif

#if defined(CONFIG_LWM2M_CARRIER)
#include <lwm2m_carrier.h>
#endif

#include <dk_buttons_and_leds.h>

#define CONFIG_LTE_CONNECT_RETRY_DELAY_S 3
#define CONFIG_MQTT_RECONNECT_DELAY_S 5
#define CONFIG_MQTT_MESSAGE_BUFFER_SIZE 128
#define CONFIG_MQTT_PAYLOAD_BUFFER_SIZE 128
#define CONFIG_MQTT_PUB_TOPIC "palmlab_gps_location"
#define CONFIG_MQTT_SUB_TOPIC "palmlab_subs_location"
#define CONFIG_MQTT_BROKER_HOSTNAME "broker.emqx.io"
#define CONFIG_MQTT_CLIENT_ID "palmlab_thingy91"
#define CONFIG_MQTT_BROKER_PORT 1883


double latt, lon, acc, res;

static K_SEM_DEFINE(location_event, 0, 1);
static K_SEM_DEFINE(lte_connected, 0, 1);
static K_SEM_DEFINE(time_update_finished, 0, 1);


/* Buffers for MQTT client. */
static uint8_t rx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t tx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t payload_buf[CONFIG_MQTT_PAYLOAD_BUFFER_SIZE];

static struct mqtt_client client;
static struct sockaddr_storage broker;

static struct pollfd fds;

#if defined(CONFIG_MQTT_LIB_TLS)
static int certificates_provision(void)
{
    int err = 0;
    LOG_INF("Provisioning certificates");
#if defined(CONFIG_NRF_MODEM_LIB) && defined(CONFIG_MODEM_KEY_MGMT)

    err = modem_key_mgmt_write(CONFIG_MQTT_TLS_SEC_TAG,
                   MODEM_KEY_MGMT_CRED_TYPE_CA_CHAIN,
                   CA_CERTIFICATE,
                   strlen(CA_CERTIFICATE));
    if (err) {
        LOG_ERR("Failed to provision CA certificate: %d", err);
        return err;
    }

#elif defined(CONFIG_BOARD_QEMU_X86) && defined(CONFIG_NET_SOCKETS_SOCKOPT_TLS)
    err = tls_credential_add(CONFIG_MQTT_TLS_SEC_TAG,
                 TLS_CREDENTIAL_CA_CERTIFICATE,
                 CA_CERTIFICATE,
                 sizeof(CA_CERTIFICATE));
    if (err) {
        LOG_ERR("Failed to register CA certificate: %d", err);
        return err;
    }
#endif

    return err;
}
#endif /* defined(CONFIG_MQTT_LIB_TLS) */


#if defined(CONFIG_LWM2M_CARRIER)
K_SEM_DEFINE(carrier_registered, 0, 1);
int lwm2m_carrier_event_handler(const lwm2m_carrier_event_t *event)
{
    switch (event->type) {
    case LWM2M_CARRIER_EVENT_BSDLIB_INIT:
        LOG_INF("LWM2M_CARRIER_EVENT_BSDLIB_INIT");
        break;
    case LWM2M_CARRIER_EVENT_CONNECTING:
        LOG_INF("LWM2M_CARRIER_EVENT_CONNECTING");
        break;
    case LWM2M_CARRIER_EVENT_CONNECTED:
        LOG_INF("LWM2M_CARRIER_EVENT_CONNECTED");
        break;
    case LWM2M_CARRIER_EVENT_DISCONNECTING:
        LOG_INF("LWM2M_CARRIER_EVENT_DISCONNECTING");
        break;
    case LWM2M_CARRIER_EVENT_DISCONNECTED:
        LOG_INF("LWM2M_CARRIER_EVENT_DISCONNECTED");
        break;
    case LWM2M_CARRIER_EVENT_BOOTSTRAPPED:
        LOG_INF("LWM2M_CARRIER_EVENT_BOOTSTRAPPED");
        break;
    case LWM2M_CARRIER_EVENT_REGISTERED:
        LOG_INF("LWM2M_CARRIER_EVENT_REGISTERED");
        k_sem_give(&carrier_registered);
        break;
    case LWM2M_CARRIER_EVENT_DEFERRED:
        LOG_INF("LWM2M_CARRIER_EVENT_DEFERRED");
        break;
    case LWM2M_CARRIER_EVENT_FOTA_START:
        LOG_INF("LWM2M_CARRIER_EVENT_FOTA_START");
        break;
    case LWM2M_CARRIER_EVENT_REBOOT:
        LOG_INF("LWM2M_CARRIER_EVENT_REBOOT");
        break;
    case LWM2M_CARRIER_EVENT_ERROR:
        LOG_ERR("LWM2M_CARRIER_EVENT_ERROR: code %d, value %d",
            ((lwm2m_carrier_event_error_t *)event->data)->code,
            ((lwm2m_carrier_event_error_t *)event->data)->value);
        break;
    default:
        LOG_WRN("Unhandled LWM2M_CARRIER_EVENT: %d", event->type);
        break;
    }

    return 0;
}
#endif /* defined(CONFIG_LWM2M_CARRIER) */

// print a new strings without a null termination
static void data_print(uint8_t *prefix, uint8_t *data, size_t len)
{
    char buf[len + 1];

    memcpy(buf, data, len);
    buf[len] = 0;
    printk(buf);
}

// publish data to configured topic
static int data_publish(struct mqtt_client *c, enum mqtt_qos qos, uint8_t *data, size_t len)
{
    struct mqtt_publish_param param;

    param.message.topic.qos = qos;
    param.message.topic.topic.utf8 = CONFIG_MQTT_PUB_TOPIC;
    param.message.topic.topic.size = strlen(CONFIG_MQTT_PUB_TOPIC);
    param.message.payload.data = data;
    param.message.payload.len = len;
    param.message_id = sys_rand32_get();
    param.dup_flag = 0;
    param.retain_flag = 0;

    data_print("Publishing: ", data, len);
    printk("to topic: %s len: %u",
        CONFIG_MQTT_PUB_TOPIC,
        (unsigned int)strlen(CONFIG_MQTT_PUB_TOPIC));

    return mqtt_publish(c, &param);
}

// subscribe to configured topic
static int subscribe(void)
{
    struct mqtt_topic subscribe_topic = {
        .topic = {
            .utf8 = CONFIG_MQTT_SUB_TOPIC,
            .size = strlen(CONFIG_MQTT_SUB_TOPIC)
        },
        .qos = MQTT_QOS_1_AT_LEAST_ONCE
    };

    const struct mqtt_subscription_list subscription_list = {
        .list = &subscribe_topic,
        .list_count = 1,
        .message_id = 1234
    };

    printk("Subscribing to: %s len %u", CONFIG_MQTT_SUB_TOPIC,
        (unsigned int)strlen(CONFIG_MQTT_SUB_TOPIC));

    return mqtt_subscribe(&client, &subscription_list);
}

// get the payload to the configured topic as a client
static int publish_get_payload(struct mqtt_client *c, size_t length)
{
    int ret;
    int err = 0;

    if (length > sizeof(payload_buf)) {
        err = -EMSGSIZE;
    }

    while (length > sizeof(payload_buf)) {
        ret = mqtt_read_publish_payload_blocking(
                c, payload_buf, (length - sizeof(payload_buf)));
        if (ret == 0) {
            return -EIO;
        } else if (ret < 0) {
            return ret;
        }

        length -= ret;
    }

    ret = mqtt_readall_publish_payload(c, payload_buf, length);
    if (ret) {
        return ret;
    }
    return err;
}

// MQTT event handler
void mqtt_evt_handler(struct mqtt_client *const c,
              const struct mqtt_evt *evt)
{
    int err;

    switch (evt->type) {
    case MQTT_EVT_CONNACK:
        if (evt->result != 0) {
            printk("MQTT connect failed: %d", evt->result);
            break;
        }

        printk("MQTT client connected");
        subscribe();
        break;

    case MQTT_EVT_DISCONNECT:
        printk("MQTT client disconnected: %d", evt->result);
        break;

    case MQTT_EVT_PUBLISH: {
        const struct mqtt_publish_param *p = &evt->param.publish;

        printk("MQTT PUBLISH result=%d len=%d",
            evt->result, p->message.payload.len);
        err = publish_get_payload(c, p->message.payload.len);

        if (p->message.topic.qos == MQTT_QOS_1_AT_LEAST_ONCE) {
            const struct mqtt_puback_param ack = {
                .message_id = p->message_id
            };

            /* Send acknowledgment. */
            mqtt_publish_qos1_ack(&client, &ack);
        }

        if (err >= 0) {
            data_print("Received: ", payload_buf,
                p->message.payload.len);
            /* Echo back received data */
            data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE,
                payload_buf, p->message.payload.len);
        } else if (err == -EMSGSIZE) {
            printk("Received payload (%d bytes) is larger than the payload buffer "
                "size (%d bytes).",
                p->message.payload.len, sizeof(payload_buf));
        } else {
            printk("publish_get_payload failed: %d", err);
            printk("Disconnecting MQTT client...");

            err = mqtt_disconnect(c);
            if (err) {
                printk("Could not disconnect: %d", err);
            }
        }
    } break;

    case MQTT_EVT_PUBACK:
        if (evt->result != 0) {
            printk("MQTT PUBACK error: %d", evt->result);
            break;
        }

        printk("PUBACK packet id: %u", evt->param.puback.message_id);
        break;

    case MQTT_EVT_SUBACK:
        if (evt->result != 0) {
            printk("MQTT SUBACK error: %d", evt->result);
            break;
        }

        printk("SUBACK packet id: %u", evt->param.suback.message_id);
        break;

    case MQTT_EVT_PINGRESP:
        if (evt->result != 0) {
            printk("MQTT PINGRESP error: %d", evt->result);
        }
        break;

    default:
        printk("Unhandled MQTT event type: %d", evt->type);
        break;
    }
}

// initialize the broker
static int broker_init(void)
{
    int err;
    struct addrinfo *result;
    struct addrinfo *addr;
    struct addrinfo hints = {
        .ai_family = AF_INET,
        .ai_socktype = SOCK_STREAM
    };

    err = getaddrinfo(CONFIG_MQTT_BROKER_HOSTNAME, NULL, &hints, &result);
    if (err) {
        printk("getaddrinfo failed: %d", err);
        return -ECHILD;
    }

    addr = result;

    /* Look for address of the broker. */
    while (addr != NULL) {
        /* IPv4 Address. */
        if (addr->ai_addrlen == sizeof(struct sockaddr_in)) {
            struct sockaddr_in *broker4 =
                ((struct sockaddr_in *)&broker);
            char ipv4_addr[NET_IPV4_ADDR_LEN];

            broker4->sin_addr.s_addr =
                ((struct sockaddr_in *)addr->ai_addr)
                ->sin_addr.s_addr;
            broker4->sin_family = AF_INET;
            broker4->sin_port = htons(CONFIG_MQTT_BROKER_PORT);

            inet_ntop(AF_INET, &broker4->sin_addr.s_addr,
                  ipv4_addr, sizeof(ipv4_addr));
            printk("IPv4 Address found %s", log_strdup(ipv4_addr));

            break;
        } else {
            printk("ai_addrlen = %u should be %u or %u",
                (unsigned int)addr->ai_addrlen,
                (unsigned int)sizeof(struct sockaddr_in),
                (unsigned int)sizeof(struct sockaddr_in6));
        }

        addr = addr->ai_next;
    }

    freeaddrinfo(result);
    return err;
}

#if defined(CONFIG_NRF_MODEM_LIB)
#define IMEI_LEN 15
#define CGSN_RESPONSE_LENGTH (IMEI_LEN + 6 + 1) /* Add 6 for \r\nOK\r\n and 1 for \0 */
#define CLIENT_ID_LEN sizeof("nrf-") + IMEI_LEN
#else
#define RANDOM_LEN 10
#define CLIENT_ID_LEN sizeof(CONFIG_BOARD) + 1 + RANDOM_LEN
#endif /* defined(CONFIG_NRF_MODEM_LIB) */

// get the client id information
static const uint8_t* client_id_get(void)
{
    static uint8_t client_id[MAX(sizeof(CONFIG_MQTT_CLIENT_ID),
                     CLIENT_ID_LEN)];

    if (strlen(CONFIG_MQTT_CLIENT_ID) > 0) {
        snprintk(client_id, sizeof(client_id), "%s",
             CONFIG_MQTT_CLIENT_ID);
        goto exit;
    }

#if defined(CONFIG_NRF_MODEM_LIB)
    char imei_buf[CGSN_RESPONSE_LENGTH + 1];
    int err;

    err = nrf_modem_at_cmd(imei_buf, sizeof(imei_buf), "AT+CGSN");
    if (err) {
        printk("Failed to obtain IMEI, error: %d", err);
        goto exit;
    }

    imei_buf[IMEI_LEN] = '\0';

    snprintk(client_id, sizeof(client_id), "nrf-%.*s", IMEI_LEN, imei_buf);
#else
    uint32_t id = sys_rand32_get();
    snprintk(client_id, sizeof(client_id), "%s-%010u", CONFIG_BOARD, id);
#endif /* !defined(NRF_CLOUD_CLIENT_ID) */

exit:
    printk("client_id = %s", log_strdup(client_id));

    return client_id;
}

// initialize client for MQTT
static int client_init(struct mqtt_client *client)
{
    int err;

    mqtt_client_init(client);

    err = broker_init();
    if (err) {
        printk("Failed to initialize broker connection");
        return err;
    }

    /* MQTT client configuration */
    client->broker = &broker;
    client->evt_cb = mqtt_evt_handler;
    client->client_id.utf8 = client_id_get();
    client->client_id.size = strlen(client->client_id.utf8);
    client->password = NULL;
    client->user_name = NULL;
    client->protocol_version = MQTT_VERSION_3_1_1;

    /* MQTT buffers configuration */
    client->rx_buf = rx_buffer;
    client->rx_buf_size = sizeof(rx_buffer);
    client->tx_buf = tx_buffer;
    client->tx_buf_size = sizeof(tx_buffer);

    /* MQTT transport configuration */
    #if defined(CONFIG_MQTT_LIB_TLS)
        struct mqtt_sec_config *tls_cfg = &(client->transport).tls.config;
        static sec_tag_t sec_tag_list[] = { CONFIG_MQTT_TLS_SEC_TAG };

        LOG_INF("TLS enabled");
        client->transport.type = MQTT_TRANSPORT_SECURE;

        tls_cfg->peer_verify = CONFIG_MQTT_TLS_PEER_VERIFY;
        tls_cfg->cipher_count = 0;
        tls_cfg->cipher_list = NULL;
        tls_cfg->sec_tag_count = ARRAY_SIZE(sec_tag_list);
        tls_cfg->sec_tag_list = sec_tag_list;
        tls_cfg->hostname = CONFIG_MQTT_BROKER_HOSTNAME;

        #if defined(CONFIG_NRF_MODEM_LIB)
            tls_cfg->session_cache = IS_ENABLED(CONFIG_MQTT_TLS_SESSION_CACHING) ?
                        TLS_SESSION_CACHE_ENABLED :
                        TLS_SESSION_CACHE_DISABLED;
        #else
            /* TLS session caching is not supported by the Zephyr network stack */
            tls_cfg->session_cache = TLS_SESSION_CACHE_DISABLED;

        #endif
    #else
        client->transport.type = MQTT_TRANSPORT_NON_SECURE;
    #endif

    return err;
}

// initialize file descriptor structure that will be used by poll
static int fds_init(struct mqtt_client *c)
{
    if (c->transport.type == MQTT_TRANSPORT_NON_SECURE) {
        fds.fd = c->transport.tcp.sock;
    } else {
#if defined(CONFIG_MQTT_LIB_TLS)
        fds.fd = c->transport.tls.sock;
#else
        return -ENOTSUP;
#endif
    }

    fds.events = POLLIN;

    return 0;
}

// configure modem that provide LTE Link. It will block any information until the connection established successfully.
static int modem_configure(void)
{
    #if defined(CONFIG_LTE_LINK_CONTROL)
        /* Turn off LTE power saving features for a more responsive demo. Also,
        * request power saving features before network registration. Some
        * networks rejects timer updates after the device has registered to the
        * LTE network.
        */
        printk("Disabling PSM and eDRX");
        lte_lc_psm_req(false);
        lte_lc_edrx_req(false);

        if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
            /* Do nothing, modem is already turned on
            * and connected.
            */
        } else {
            #if defined(CONFIG_LWM2M_CARRIER)
            /* Wait for the LWM2M_CARRIER to configure the modem and
            * start the connection.
            */
                printk("Waitng for carrier registration...");
                k_sem_take(&carrier_registered, K_FOREVER);
                printk("Registered!");
            #else /* defined(CONFIG_LWM2M_CARRIER) */
                int err;

                printk("Connecting to NB-IOT Network.");
                err = lte_lc_init_and_connect();
                if (err) {
                    printk("Failed to establish NB-IOT connection: %d", err);
              %C2%A0     return err;
                }
                printk("Connected to the network!");
            #endif /* defined(CONFIG_LWM2M_CARRIER) */
        }
    #endif /* defined(CONFIG_LTE_LINK_CONTROL) */
    return 0;
}

// set date time for event handling
static void date_time_evt_handler(const struct date_time_evt *evt)
{
    k_sem_give(&time_update_finished);
}

// event handling for LTE connection
static void lte_event_handler(const struct lte_lc_evt *const evt)
{
    switch (evt->type) {
    case LTE_LC_EVT_NW_REG_STATUS:
        if ((evt->nw_reg_status == LTE_LC_NW_REG_REGISTERED_HOME) ||
             (evt->nw_reg_status == LTE_LC_NW_REG_REGISTERED_ROAMING)) {
            printk("Connected to NB-IOT\n");
            k_sem_give(&lte_connected);
        }
        break;
    default:
        break;
    }
}

// get handling location event
static void location_event_handler(const struct location_event_data *event_data)
{
    switch (event_data->id) {
    case LOCATION_EVT_LOCATION:
        printk("Got location:\n");
        printk("  method: %s\n", location_method_str(event_data->location.method));
        printk("  latitude: %.06f\n", event_data->location.latitude);
        printk("  longitude: %.06f\n", event_data->location.longitude);
        printk("  accuracy: %.01f m\n", event_data->location.accuracy);
        printk("  Google maps URL: https://maps.google.com/?q=%.06f,%.06f\n\n",
            event_data->location.latitude, event_data->location.longitude);
        char temp_latt[12];
        char temp_long[12];
        char temp_acc[12];
        char result[50];

        gcvt(event_data->location.latitude, 12, temp_latt);
        latt = atof(temp_latt);
        gcvt(event_data->location.longitude, 12, temp_long);
        lon = atof(temp_long);
        gcvt(event_data->location.accuracy, 12, temp_acc);
        acc = atof(temp_acc);
        res = 200;
        sprintf(result, "%f %f %f", latt, lon, acc);
        int result_len = strlen(result);
        printk(result);
        printk("Publishing message to MQTT Broker.");
        data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE,
                result, result_len);
        printk("Done publishing.");
        break;

    case LOCATION_EVT_TIMEOUT:
        printk("Retrieving location timed out\n\n");
        break;

    case LOCATION_EVT_ERROR:
        printk("Retrieving location failed\n\n");
        break;

    case LOCATION_EVT_GNSS_ASSISTANCE_REQUEST:
        printk("Retrieving location assistance requested (A-GPS). Not doing anything.\n\n");
        break;

    case LOCATION_EVT_GNSS_PREDICTION_REQUEST:
        printk("Retrieving location assistance requested (P-GPS). Not doing anything.\n\n");
        break;

    default:
        printk("Retrieving location: Unknown event\n\n");
        break;
    }

    k_sem_give(&location_event);
}

static void location_event_wait(void)
{
    k_sem_take(&location_event, K_FOREVER);
}
 
static void location_with_fallback_get(void)
{
    int err;
    struct location_config config;
    enum location_method methods[] = {LOCATION_METHOD_GNSS, LOCATION_METHOD_CELLULAR};

    location_config_defaults_set(&config, ARRAY_SIZE(methods), methods);
    config.methods[0].gnss.timeout = 1;
    config.methods[1].cellular.timeout = 30;

    printk("Requesting location with short GNSS timeout to trigger fallback to cellular...\n");

    err = location_request(&config);
    if (err) {
        printk("Requesting location failed, error: %d\n", err);
        return;
    }

    location_event_wait();
}


static void location_default_get(void)
{
    int err;

    printk("Requesting location with the default configuration...\n");

    err = location_request(NULL);
    if (err) {
        printk("Requesting location failed, error: %d\n", err);
        return;
    }

    location_event_wait();
}

static void location_gnss_low_accuracy_get(void)
{
    int err;
    struct location_config config;
    enum location_method methods[] = {LOCATION_METHOD_GNSS};

    location_config_defaults_set(&config, ARRAY_SIZE(methods), methods);
    config.methods[0].gnss.accuracy = LOCATION_ACCURACY_LOW;

    printk("Requesting low accuracy GNSS location...\n");

    err = location_request(&config);
    if (err) {
        printk("Requesting location failed, error: %d\n", err);
        return;
    }

    location_event_wait();
}

/**
 * @brief Retrieve location with GNSS high accuracy.
 */
static void location_gnss_high_accuracy_get(void)
{
    int err;
    struct location_config config;
    enum location_method methods[] = {LOCATION_METHOD_GNSS};

    location_config_defaults_set(&config, ARRAY_SIZE(methods), methods);
    config.methods[0].gnss.accuracy = LOCATION_ACCURACY_HIGH;

    printk("Requesting high accuracy GNSS location...\n");

    err = location_request(&config);
    if (err) {
        printk("Requesting location failed, error: %d\n", err);
        return;
    }

    location_event_wait();
}

/**
 * @brief Retrieve location periodically with GNSS as first priority and cellular as second.
 */
static void location_gnss_periodic_get(void)
{
    int err;
    printk("retrieving location.");
    struct location_config config;
    enum location_method methods[] = {LOCATION_METHOD_GNSS, LOCATION_METHOD_CELLULAR};

    location_config_defaults_set(&config, ARRAY_SIZE(methods), methods);
    config.interval = 30;

    printk("Requesting 30s periodic GNSS location with cellular fallback...\n");

    err = location_request(&config);
    if (err) {
        printk("Requesting location failed, error: %d\n", err);
        return;
    }
}

int main(void)
{
    int err;
    printk("Starting firmwre.\n");
    uint32_t connect_attempt = 0;
    printk("checking time settings.\n");
    if (IS_ENABLED(CONFIG_DATE_TIME)) {
        date_time_register_handler(date_time_evt_handler);
    }

    do {
        printk("configuring modem.\n");
        err = modem_configure();
        if (err) {
            printk(".");
            k_sleep(K_SECONDS(CONFIG_LTE_CONNECT_RETRY_DELAY_S));
        }
    } while (err);

    printk("Modem Connected.\n");
    printk("Connecting to NB-IOT Signals.\n");

    lte_lc_init();
    lte_lc_register_handler(lte_event_handler);
    printk("Connected to NB-IOT Signals.");

    /* Enable PSM. */
    // lte_lc_psm_req(true);
    // lte_lc_connect();
    // k_sem_take(&lte_connected, K_FOREVER);
    // printk("Enabling PSM.");

do_connect:
    if (connect_attempt++ > 0) {
        printk(".");
        k_sleep(K_SECONDS(1));
    }
    printk("\n");
    err = mqtt_connect(&client);
    if (err != 0) {
        printk("mqtt connection status : %d\n", err);
        goto do_connect;
    }

    printk("Connected to MQTT server.\n");
    printk("Starting program..\n");
    k_sleep(K_SECONDS(CONFIG_MQTT_RECONNECT_DELAY_S));

    while (1) {
        printk("re-doing program");
        err = location_init(location_event_handler);
        if (err) {
            printk("Initializing the Location library failed, error: %d\n", err);
            return -1;
        }

        err = mqtt_live(&client);
        if ((err != 0) && (err != -EAGAIN)) {
            printk("ERROR: mqtt_live: %d", err);
            break;
        }

        location_with_fallback_get();
        location_default_get();
        location_gnss_low_accuracy_get();
        location_gnss_high_accuracy_get();
        location_gnss_periodic_get();
    }
    err = mqtt_disconnect(&client);
    if (err) {
        printk("Could not disconnect MQTT.");
    }
    goto do_connect;
}

Thanks.

[Einarh]

What specific function returns the error code?

[azwawe]

it is on line 758, mqtt_connect(&client).

[Einarh]

It looks like you're doing something very similar to this sample setup, which should work:

http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/connectivity/networking/api/mqtt.html

The first thing I notice is that you're using the arrow operator where the sample uses the dot operator (client->broker vs client.broker).

Any reason you've done this?

Since you get an error related to the input, the first thing I would do is check that the client object looks like you expect before it's given to the mqtt_connect function.

Try to print all the values in your client object and check that they are what you expect.

-Einar