Why can't the mobile phone send short messages?

Every mobile phone has "SMS Center Settings", which can generally be found in SMS settings or mobile phone network settings, but different mobile phone menus display different names. For example, my mobile phone says "information center settings", and the old mobile phone I used before seems to say "message network center settings". I used to use an old mobile phone that couldn't send text messages because one of the settings in the SMS center was tampered with. Of course, there are many reasons for tampering, so I won't delve into it. Just change the settings back to the default values. If you don't know how to change it, you can ask the mobile phone after sale. If not, you can restore the default appearance. I don't know if your 5233 is the reason. I hope this experience will help you.