Why did the iphone message fail to be sent?

Iphone4 SMS sending failed, and the solution is as follows;

Check whether the mobile phone signal and SIM card status are normal, and confirm whether to stop; Check whether the send key is bright and clickable. If you can't click Send after entering the text, the "Send" key is still gray. Please turn off "Show Subject Bar" in Settings > SMS >.

If it is a group message, and the numbers are entered manually, make sure to use line breaks instead of spaces to separate each number.

After the above problems are eliminated, you can first check whether the number of the SMS center is correct. If it is not correct, you can delete it first and then reset it. After setting, you can check whether the number of the SMS center is correct again. The specific operation mode is as follows:

1. Inquire about the set SMS center number: dial *#5005*7672# with iPhone.

2. Delete SMS center number: dial ##5005*7672# with iPhone.

3. Set SMS center number: dial *5005*7672*+86 SMS center number # with iPhone.

The system is still not fully recovered. You can consult manually and solve it within 24 hours, and you can update all the data of SMS.