I’d be interested to know how many of us are officers. All the characters I’ve checked are.
this is happening to all of my characters too :C
Same issue. No guild chat. No Guild Finder.
I can see the Guild MOTD though!
Same - I can see guildies log in/out, and see them get achievements, but no chat. Party chat/whispers are fine.
I’m having the same issue as well. Was working fine earlier today 
I am also having the same issue
Tossing in a reply in as another person who’s having this problem
Im having the same problem on several of my toons, when I mouse over guild icon it says Guild and Communities unavailable…It does work on one of my toons but not the others
Yep, same problem guild chat gone on characters, most unable to open guild pane as well. it’s greyed out.
Same and I am the guild leader of two active guilds on Hyjal and Malfurion, and a community that links them.