Users of O2's mobile broadband service encountered problems when trying to access Facebook earlier in the week.
News of the hitch first became apparent on the O2 customer forum on Tuesday (February 17th) morning.
A temporary solution was found in the form of an iPhone-based interface used for Facebook, which allowed disconnected networkers to check their accounts.
"We have worked with Facebook and a third party supplier to establish a resolution to the problem," explained an O2 spokesman to Web User.
"The issue was resolved by a routing change in the third party's network. The cause of the issue is currently under investigation."
The mobile broadband provider confirmed that Facebook had been unavailable from Monday (February 16th) evening through to Tuesday afternoon.