Why can my mobile phone only send MMS but not SMS?

There are several reasons why the mobile phone can't send MMS:

1. The mobile phone does not support MMS function;

2. The parameter setting of mobile phone MMS is incorrect;

3. The size of the sent MMS exceeds 50K；;

4. The MMS outbox and inbox are full;

In addition to the above simple troubleshooting, you can turn off your phone or change your mobile phone to test it, but it still won't solve it. You can contact the manual customer service for processing.