Was it working before?
What is the actual verbatim message?
What happens if you do a manual scan for networks?
Can you see and connect to 48?
Is roaming/data roaming enabled?
Hope this helps.
If you're still having issues, can you take you SIM out of your handset, give it a little wipe at the back to clean it and re-insert it? Once rebooted again, please try your services!
We would also appreciate if you could try your 48 SIM in another unlocked handset to determine if the fault is handset/settings related.
Can you also provide the part of Ireland you're in so I can check for Coverage Issues?
If you can get back to me with this information we can investigate this further and get to the bottom of the problem.