Problem connecting to ISP

Good morning.

Module: EC25;
Revision: EC25AFAR62A01M4G_BETA0515.

I have been facing difficulties to establish a GPRS connection with one of the four greatest brazilian ISP.
The sim cards from two of them work perfectly, however, to the ISP “Oi” we could not connect to the peer.
We have ran the following commands (the arrow indicates the results):
AT+CFUN? -> +CFUN: 1
AT+COPS? -> +COPS: 0
AT+COPN -> More than one thousand results, among them “Oi” ISP appears with the codes: +COPN: “72416”,“Oi”, +COPN: “72424”,“Oi” and +COPN: “72431”,“Oi”.

With the outcome of the last AT command, we tried to register to the network operator:

All of them returned “+CME ERROR: 30”

With my smartphone, the simcard connection works flawlessly. Does anyone know what is happening?

Hi Andre.machoski

According to the information you provided, you are not connected to the network. You should make sure that the 4G antenna is plugged in and meets the module requirements.
If your antenna is connected properly,i suggest you to check the network connection by running the following AT command.
AT+CEREG? Determine whether to connect to the 4G network.
AT+CPIN? Determine whether the card is identified.
AT+CFUN=0,AT+CFUN=1 Redo your web search
AT+QCFG=“nwscanmode” Check whether the module locks the network system. Return 0 for automatic and 3 for LTE ONLY.