This kind of issue would only happen in GSM gateway.
No USSD response from carrier. USSD response display abnormally.
1. USSD theory. Go to the first chapter to get basic understanding of the function. USSD Flow
2. GSM trunk registration. Check if your GSM trunk is registered or not.
3. SIM card balance. Check if your SIM card own enough balance.
4. USSD code. Check if your USSD is used correctly according to the carrier USSD code list.
5. Contact carrier. Contact carrier support to see what happened.
If issue persists after the checklist, please post us the following information via our support portal.
- Problem description.
- Result of each step in the check list.
- Screen capture of problem.
- AT Command log. How to Get AT Command Log