Why do incoming calls turn into SMS reminders?

The reason for calling SMS is that your mobile phone can't be connected or prompted to turn off when the other party calls you. The general reasons are as follows:

1, your local signal is often bad, resulting in the phone can not be connected;

2. Your mobile phone card has been used for a long time, and the chip contacts are unstable when it is not used, resulting in the incoming call signal not coming in;

3. Or your location is where people are concentrated, and the number of service base stations reaches a peak;

4. There is a problem with the contact between the mobile phone and the mobile phone card. It is suggested that the contact part of the chip can be gently wiped with an eraser to remove the oxide.

If it is not the above reasons, it should be the mobile phone. If it is still within the 4-month warranty period, you can check it for free after sale.