A wierd one!
They're both in Group A in the euro qualifiers, but as they're not on the best of terms, they were unable to agree a venue for the games, so UEFA have said the games will simply not go ahead, and both countries will forfeit the points.
Armenia were happy to play home and away, Azerbaijan weren't going to host Armenia and wanted a neutral ground for both games, they couldn't agree and so UEFA stepped in.
Sound very harsh on Armenia.