FONA not connecting AT+CREG 0,3 Moderators: adafruit_support_bill, adafruit

[jpuigdef]

Hi, we operate several fona808, all of them with success except for one that suddenly ceased to connect to the network. When testing it with the FONATest utility, we see that when attempting to connect to the network it starts responding AT+CREG 0,2 (searching) for some time and then it falls into AT+CREG 0,3 (access denied).

The same SIM works fine on other FONA's, and other SIMS (even from other providers) do not change this behaviour.
The CCID of the SIM is correctly read, the battery is fine and works well with other FONAs, and the RSSI signal strength is correct (-78dBm)
We tried to send ATZ, restart, remove batt, etc, without success.

We would appreciate any suggestion on this issue.

Thanks

[adafruit_support_mike]

Have you tried swapping antennas?

From the list of things that do work, my first suspect would be a weak signal making it impossible for the FONA to finish its authentication with the cell tower. The RSSI only tells you how well the FONA can hear the tower, not how well the tower can hear the FONA.

[jpuigdef]

thanks Mike,

yes I've tried to swap antennas without success (the antennas were working fine in other fonas in the same location).

I also noticed during one of the trials that RSSI dropped without any apparent reason to -115dBm. Would that mean that de fona hardware itself is failing?

The fona was working fine for some months (october19-april20) and then suddenly ceased to connect.

Thanks
joan

[adafruit_support_mike]

It's possible that something in the FONA is starting to go bad, yes. I'm afraid it's outside our 30-day return/replace period though.