When did it start happening?
You may need to contact 48 support.
A few people seem to be reporting similar problems at the moment so maybe it's a general issue.
Can't say that I've noticed it myself so far in Dublin city centre.
Hope this helps.
Announcement on the main site:
We are experiencing problems with the network at the moment which is affecting calls, texts and mobile data. We're sorry about any inconvenience caused by this. The network engineers are aware of the problem and are working on getting this resolved as soon as possible.