Why can't the send button of iphone 4 send SMS be grayed out?

The send button for sending SMS on iPhone4 is grayed out and cannot be sent. The solution is as follows:

Check whether the cell phone signal is normal first.

Then check whether the SIM card status is normal.

Then check whether the send key is displayed in bright color and is 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.