GSM A6 Module doesn't receive SMS

When i send a message from my phone to the SIM inserted in the phone, only the sender phone number ,date and time are displayed on the serial monitor

I’m not familiar with the A6, but don’t you need to send a AT+CMGR=1 command to read the contents of a message? (Or change the “1” by the actual index of the message in the storage).

It gives me ERROR:321 if index 1,2 or 3, i didn’t try other values.
I tried AT+CMGL=“ALL” it should list all the messages but it doesn’t give anything back.

And does this also happen if you send the SMS from another phone to the A6?