New phone not registered on network

[BWJazz]

I am on an existing O2 pay monthly contract and have been given a new unlocked phone. I moved the SIM card to the new phone and made a call from my landline to the new phone which rang and then from the new phone to my landline which also worked. Now, about 90 minutes later I get the message "Not registered on network". w Can anybody help me to fix this please?

[MI5 · Accepted solution]

@BWJazz 

Try the sim back in your old phone and if it works on that the new phone is faulty or barred.

If it doesn't work, your sim has failed so go into any O2 shop for a replacement or call cust service to post you one out Guide: How to find help & contact O2 

[Marjo]

Hi @BWJazz , how did it go with your new phone and the issue you were having when you last posted? It would be lovely to hear back from you!