nrf9160 fails to connect to NB-IoT

[frax84]

Hello,

lately i've not been able to connect to NB-IoT network as i did before.

Long story short:

I'm working with nrf9160 since 3 months and i have been able to connect without any issues to NB-IoT national network. Lately (last month) i had always bigger problems trying to connect. At first it still connected sometimes, but now i'm not able to connect anymore. One month ago, after first problems arised i updated to modem firmware to 1.2.0 with no luck. For such reason, i opened THIS TICKET because i was getting getaddrinfo error -11. Apparently, using manual DNS setting i solved the problem...or so i thought...after few succesfull tries i had again the same error.

My setup:

NRF9160DK (modem firmware 1.2.0)

IBasis SIM (should roam in ROME, ITALY on NB-IoT NATIONAL NETWORK)

I'm running AT Client sample to make some tests and this is the log:

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AT+CFUN?

+CFUN: 0

OK

AT+CGDCONT?

OK

AT+CFUN=1

OK

AT+CGDCONT?

OK

AT+CFUN?

+CFUN: 1

OK

AT+CGSN=1

+CGSN: "352656100036634"

OK

AT+CGMI

Nordic Semiconductor ASA

OK

AT+CGMM

nRF9160-SICA

OK

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

AT+CFUN?
+CFUN: 0
OK
AT+CGDCONT?
OK
AT+CFUN=1
OK
AT+CGDCONT?
OK
AT+CFUN?
+CFUN: 1
OK
AT+CGSN=1
+CGSN: "352656100036634"
OK
AT+CGMI
Nordic Semiconductor ASA
OK
AT+CGMM
nRF9160-SICA
OK
AT+CGMR
mfw_nrf9160_1.2.0
OK
AT+CEMODE?
+CEMODE: 0
OK
AT%XCBAND=?%XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66)
OK
AT+CMEE?
+CMEE: 0
OK
AT+CMEE=1
OK
AT+CNEC?
+CNEC: 0
OK
AT+CNEC=24
OK
AT+CGEREP?
+CGEREP: 0,0
OK
AT+CGDCONT?
OK
AT+CGACT?
OK
AT+CGEREP=1
OK
AT+CIND=1,1,1
OK
AT+CEREG=2
OK
AT+CEREG?
+CEREG: 2,4,"FFFE","FFFFFFFF",9
OK
AT%CESQ=1
OK
AT+CESQ
+CESQ: 99,99,255,255,255,255
OK
AT%XSIM=1
OK
AT%XSIM?
%XSIM: 1
OK
AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
204080813513852
OK
%CESQ: 68,3,23,3
+CEREG: 2,"7B88","04DCDD88",9
+CNEC_ESM: 38,0
+CNEC_EMM: 19
+CEREG: 2,"90EA","010F0971",9
+CNEC_EMM: 13
%CESQ: 255,0,255,0
+CEREG: 2,"FFFE","FFFFFFFF",9
%CESQ: 62,3,24,3
+CEREG: 2,"80F3","04987148",9
+CNEC_EMM: 15+CEREG: 4,"80F3","04987148",9
%CESQ: 255,0,255,0
+CEREG: 4,"FFFE","FFFFFFFF",9
%CESQ: 63,3,24,3
+CEREG: 4,"80F3","04987148",9
AT+CGDCONT?+CGDCONT: 0,"IP","","",0,0
OK+CEREG: 2,"7B88","04DCDD88",9
+CNEC_ESM: 38,0
+CNEC_EMM: 19
%CESQ: 68,3,24,3
+CEREG: 4,"80F3","04987148",9
%CESQ: 63,3,24,3
+CEREG: 2,"7B88","04DCDD88",9
%CESQ: 68,3,24,3
%CESQ: 68,3,29,4
+CNEC_ESM: 38,0
+CNEC_EMM: 19
+CEREG: 4,"80F3","04987148",9
%CESQ: 63,3,29,4
%CESQ: 63,3,24,3
+CEREG: 2,"7B88","04DCDD88",9
%CESQ: 68,3,24,3
%CESQ: 68,3,29,4
AT+COPS?
+COPS: 0
OK
AT+COPS=?
+COPS: (1,"","","22288",9),(1,"","","22210",9),(1,"","","22201",9)

This is the screenshot of my LTE Link Control panel:

Some final questions that could be useful to address this issue:

1) If i run AT+CGDCONT? command i get "+CGDCONT: 0,"IP","","",0,0". I expected something like "+CGDCONT: 0,"IP","ibasis.iot","",0,0. Is it normal?

2) In THIS page i noted that Vodafone has Modem firmware certification only for version 1.1.0. In the case i'm connecting to Vodafone NB-IoT network (not sure about it, didn't verify when it was working), could this be the issue?

3) If the log above there are 2 lines about error codes from ESM, EMM, in particular error 19 (Network Failure). Does it refer to a problem external to the board? Does it mean is a network-side problem?

Thank you,

Frax