1. Check whether the number is overdue. If it is overdue, you can recharge it first and then try to send it.
2. Check whether the Internet access function of the mobile phone is normal. You can send or receive MMS only after Internet access is enabled.
3, you can turn off the phone and check it to see if it is a hardware problem of the phone;
4. Check whether the MMS outbox and inbox are full, and then try to send it after deleting it;