Hello everyone,
The cellular interface is down even if there is signal, the SIM card is working and the configuration from the cellular interface is correct.
Steps and solution:
1. First check if the SIM card is a 3G or a 4G SIM. In this case, the cellular interface was flapping between the 3G and 4G.
2. Display the command display cellular interface many times to check the state of the cellular interface.
3. Since the configuration was correct, I've tried to change the band to LTE only “mode lte lte-only” and the device was not able to connect to 4G directly and the cellular interface was also DOWN so I change the band to 3G : “mode lte wcdma-only” and the interface goes UP and the device was able to connect correctly.
So I confirmed that the SIM card was a 3G sim card not a 4G SIM and I configured this command “mode lte wcdma-gsm”.
That is all I want to share with you!