MKR GSM 1400 sms.read doesnt work

Official Hardware MKR Family MKR GSM 1400
10

weird. Do you have another SIM card you could test with?

try printing the HEX codes instead of the characters

 while ((c = sms.read()) != -1) {
      Serial.print((byte)c, HEX); Serial.write(' ');
    }