Modem are not able to get Date and time from NTP

[Roman Veselskyi]

Hello,

We faced with issue in which we are not able to get the time from the network and because we don't have time, we can't use JWT. As I understood issue is because of DNS but I don't know how to investigate it and need your help. 

[00:00:16.249,328] <dbg> date_time: date_time_update_work_fn: Updating date time UTC...
[00:00:16.249,359] <dbg> date_time: date_time_core_current_check: Date time never set
[00:00:16.249,389] <dbg> date_time: date_time_update_work_fn: Getting time from cellular network
[00:00:16.249,389] <dbg> date_time: date_time_modem_get: Modem has not got time from LTE network, so not using it
[00:00:16.249,420] <dbg> date_time: date_time_update_work_fn: Getting time from NTP server
[00:00:16.250,122] <dbg> date_time: date_time_ntp_get: Connected to LTE, performing NTP UTC time update
[00:00:16.250,427] <wrn> date_time: getaddrinfo, error: -2
[00:00:16.250,457] <dbg> date_time: date_time_ntp_get: Did not get time from NTP server ntp.uio.no, error -2
[00:00:16.250,854] <wrn> date_time: getaddrinfo, error: -2
[00:00:16.250,885] <dbg> date_time: date_time_ntp_get: Did not get time from NTP server time.google.com, error -2
[00:00:16.250,915] <wrn> date_time: Did not get time from any NTP server
[00:00:16.250,915] <dbg> date_time: date_time_update_work_fn: Did not get time from any time source
[00:00:16.250,946] <dbg> date_time: date_time_core_schedule_retry: Date time update retry in: 30 seconds

[Roman Veselskyi]

I was able to fix the issue by enabling CONFIG_PDN_LEGACY_PCO=y. However, if I understand correctly, since we plan to use these devices in multiple countries, this firmware setting will work on networks that use PCO but not on those that rely on ePCO.

How should we handle that? Is there an example we can refer to?

Also, it seems there’s no way to manually set the DNS, so the only option might be to switch between AT%XEPCO=0 and AT%XEPCO=1 on the fly.