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nrf9160 fails to connect to NB-IoT

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

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