Not able to send SMS

[ADB57]

I ported my SIM from Vodafone to O2 many years ago, and have not had any issues sending text messages. Earlier this year, I got a Samsung A14 phone, Android version 14, and I am unable to send any texts. I gather it has something to do with the fact that the SIM was ported. Can this be resolved, or is it a case of getting a new SIM with a totally different number?

[Enlli]

If it has been happily working for some time and then happened with the change of handset then it may be a setting on the phone.

Have a look at this guide first

Guide: Text Message Tips (not sent or received) 

[MI5]

@ADB57 

Check RCS settings in the message app or download Google messages from Play store and try that.

Samsung stock message app has known bugs.