What should I do if my mobile phone fails to send SMS?

Check the phone bill first to see if there is any phone bill. (The mobile phone bill is always deducted, and the phone bill disappears inexplicably, which is normal. Then you have to check whether the other party you sent has stopped or turned off (you can't receive short messages if you stop). Other situations are network reasons, or the mobile system has blacklisted your number, so you can't send text messages. Check it yourself! That's all! Hope to adopt, thank you.