Iphone SMS can only be received, not sent. What happened?

The solution that SMS on iphone can only be received but not sent can be realized by the following steps.

1. First, on the desktop of Apple's mobile phone, click the Settings icon to enter.

2. Enter the setting interface and click the auxiliary function to enter, as shown in the figure below.

3. Then in the auxiliary function interface, click the dynamic effect to enter.

4. Finally, enter the dynamic effect interface and turn off the switch to weaken the dynamic effect. As shown below, the problem that short messages can only be received but not sent is solved.