connessione non riuscita tramite Portenta CATm1 di Arduino

dalla scheda Portenta CATM1 di Arduino ottengo sempre lo stesso errore:

[INFO][CELL]: Continue after 2 seconds

[INFO][CELL]: RSSI unknown

[INFO][CELL]: Network registration (timeout 180000 ms)

[INFO][CELL]: Continue after 4 seconds

[INFO][CELL]: RSSI unknown

[INFO][CELL]: Network registration (timeout 180000 ms)

[INFO][CELL]: Continue after 8 seconds

[INFO][CELL]: RSSI unknown

[INFO][CELL]: Network registration (timeout 180000 ms)

[INFO][CELL]: Continue after 16 seconds

[INFO][CELL]: RSSI unknown

[INFO][CELL]: Network registration (timeout 180000 ms)

[INFO][CELL]: Continue after 32 seconds

[INFO][CELL]: RSSI unknown

[INFO][CELL]: Network registration (timeout 180000 ms)

[ERR ][CELL]: CellularStateMachine failure: Registering network

[ERR ][CELL]: CellularStateMachine target state Attaching network, current state Registering network

[INFO][CELL]: CellularContext disconnected

The board was not able to register to the network…

la sim IOT si connette correttamente tramite telefono.