Why can't the mobile phone send short messages? It always shows "Failed to send, saved in Outbox"?

Case 1: Confirm whether the number of SMS center is set correctly! The mobile phone number is 13800280500. Just change it in the SMS settings. Situation 2: Confirm whether your card is down or has sent a group message. Group SMS, the mobile company will block your SMS function, just dial 10086 manual service desk to solve it. Situation 3: There is something wrong with the mobile phone. Just restore the factory settings. If yours is a smart phone, I suggest you check it, and the effect will be better.