o2 sim not working in unlocked iphone 12 mini

[Dannihilli]

I am tearing my hair out. I have set this phone up from an icloud backup of my old iphone x  BUT it won’t connect to the o2 cellular network. The SIM works fine in my old phone and when i recently upgraded it I ticked the 5G ready box.

When I go to settings/general/about/network I get a message saying ‘not available’ and when I click on this it says ‘phone not allowed’

Has anyone else had this problem and know how to resolve it. All help gratefully received.

[MI5 · Accepted solution]

@Dannihilli 

The phone would appear to be blocked.

If it came from O2 you need to call them to lift the block from the phone.