Why can't iMessage send text messages?

Because the system prohibits the sending and receiving permission of iMessage. The solution is as follows:

1. First, open the settings indicated by the arrow on the mobile phone desktop.

2. After opening the settings, click the shutdown flight mode to ensure the smooth network.

3. Next, click the message indicated by the arrow at the bottom of the page.

4. On the following page, you can see that iMessage is closed.

5. Next, click to open normal sending and receiving.