Why can't telecom mobile phones send text messages?

If the flight mode is not turned off and the mobile phone can't send and receive SMS, then the mobile phone is in arrears, and the solution is as follows:

1. First, open the SMS on the open mobile phone desktop, as shown in the figure below.

2. Then in the open page, click the plus sign in the upper right corner to edit the message, as shown in the figure below.

3. Then in the open page, edit the content of the message you want to send, and click Send, as shown in the figure below.

4. At this time, I found that the mobile phone could not send short messages because it did not turn off the flight mode, as shown in the figure below.

5. Find the flight mode and click Close, as shown in the figure below.

6. You can send short messages after turning off the flight mode, as shown in the figure below.