Why can't the Apple 6 phone address book and information be opened?

The reasons why iPhone can't send SMS and the solutions are as follows;

1. Whether the cell phone signal is normal.

2. Check whether the SIM card status is normal.

3. Check whether the send key is bright and clickable.

4. 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 >.

5. If it is a mass message and the numbers are entered manually, please make sure to separate each number with a line break instead of a space.

6. 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 the setting is completed, you can check whether the SMS center number is correct again.