What membership do you have?
EU roaming only works on Guido.
If you have Guido then it should work.
However are you using an iPhone?
If so then this issue due to the stupid way that Apple do things with iPhones could be relevant.
http://community.48months.ie/t5/Most-Popular-Questions/iPhone-abroad-issue/td-p/36862You may have to try that reconfiguration many times before it works.
Switching airplane mode on and then off and then quickly trying the reconfiguration may help.
Hope this helps.
I am not a 48 employee - if you need to contact 48 support then please
click here - if the Chat Now option does not appear on that page then keep trying until it does.