MMS not supported

[Dman7777773]

Galaxy A10 on o2 pay monthly will not send MMS messages 

[Bambino · Accepted solution]

@Dman7777773 Your data must be turned on to send an MMS. If you want to send picture messages and avoid wasting your data allowance, download WhatsApp and send your pictures over WiFi to anyone else who also has the app for free.

[pgn]

Many employ a trick to disable MMS, as each message costs something like 53p (maybe more, have not checked for a few years), here's the article below about disabling MMS, if you must use the antiquated and expensive MMS system to share pictures or URLs with your friends.

@Bambino's advice above really does work a lot better, and is free so long as WiFi is good (either 4G or 5G or domestic Broadband)    @Dman7777773 

Guide: Accidental MMS Sending and How to Avoid it 

Good luck!