Facebook and Instagram users reported an inability to connect on Monday afternoon.
The problem appeared shortly after 15.00 Greek time, according to reports collected by Downdetector.com, a service that monitors the operation of popular Internet destinations.
Globally, however, Facebook appears to be functioning normally.
Meta's two-platform issue comes just days after the previous "blackout" that made headlines around the world.
So far Meta has not clarified the nature of the problem or predicted when it might be fixed.
Source: in.gr