What is the reason why SMS can't be sent out and how to debug it?

The following reasons:

1. Please confirm that the signal strength of the mobile phone is in a normal state. If the mobile phone has no signal or the signal is weak, please go to a place with strong signal and then test it;

2. Check the storage space of mobile phone short messages, and confirm whether the mobile phone has enough space to receive information. If the space is insufficient, please clean up the space of the mobile phone;

3. Please use the complete mobile phone number when sending information;

4. Confirm whether the SMS center number is normal. Please contact the local operator for relevant SMS center numbers.

if you have any questions, please ask.