Why is the thread title "Donegal"?
What does that location have to do with this issue?
You'll need to provide a bit more information and context if you want assistance from the Community Forum.
Are you absolutely sure that the other phone is unlocked for use on any network?
What happens when you put the SIM in the other phone?
Any error messages or what's the behaviour?
What exactly works or doesn't work?
Connection to the 48 network - i.e. signal bars?
Incoming/outgoing calls?
Incoming/outgoing texts?
Mobile data?
What make and model of phone is it?
If it's an iPhone then it might need to go through the silly Apple iPhone activation process which involves the phone silently sending an SMS message to a UK activation server and this fails silently if you can't send international texts (I.e. don't have an active membership plan and sufficient cash credit on your account to pay for the international text message).
In this case putting €1 cash credit on your account, switching the phone off and on again, and waiting a little while might allow this process to happen.
If you need to contact 48 support about this then see the links in my signature below.
