IBAN Number Italian Bank

Hi, my Revolut app will not recognise an IBAN number for an Italian bank. Ive checked the number and it’s perfectly okay. Is there a reason for this? do I put in all the number including letters? Thanks in advance.

That might be a bug. Did support comment on it?

Support were no use alessandro, wanted me to wait 4 hours for a ‘live chat’
Just tried again and it worked this time, did nothing diferent to yesterday, thanks for replying.