Today, I also received a text message from China Unicom, but even the customer service could not be dialed out. Why is it restricted to use other numbers to call this machine?

Common causes and solutions of telephone failures;

1. Check whether the mobile phone is in arrears, and suggest to pay for recharging;

2. Check whether the mobile phone is set with call forwarding, flight mode on and call barring. Suggest canceling and try again;

3. Check whether the function or signal of the mobile phone is normal. It is recommended to change your mobile phone or location and try again.

4. If roaming to other places can't be used, it is recommended to check whether the local network signal is normal and whether the number has been roaming;

5. Try restarting or changing your mobile phone to see if you can answer the phone;

6. Bring your mobile phone card to the local business hall for testing or replacement.