O2 sim not working in o2 phone

[Phillipsuk]

I have given my daughter my old iPhone 5c which is an my old o2 contract phone many years ago, I have ordered her an o2 pay as you go SIM card.

Installed the sim card and for some reason it’s saying sim not supported?

Im a little confused....

[Bambino]

@Phillipsuk Is there credit on the sim? https://community.o2.co.uk/t5/How-to-Guides/How-to-Top-Up-PAYG/ba-p/1156408

Edit: Also see this: https://apn-settings.com/o2-pay-and-go-apn-settings/

http://service.o2.co.uk/IQ/SRVS/CGI-BIN/WEBCGI.EXE?New,Kb=Companion,question=ref(User):str(Mobile),C...

[MI5]

@Phillipsuk 

Try connecting to iTunes on your PC. 
Also make sure you are logged out of your old Apple ID and sign in with a new one for the new user.