I have switched over to AOL mail and it views fine in Safari (MacBook Pro MAC OS Yosemite 10.10.5), but when in Firefox (45.0.1) only a part of the left panel loads with nothing showing to the right of that.
Tried clearing history, cookies, sign out, relog in, still doing the same. Thankfully, Safari is doing fine.
To make it weirder, my wife's email had initial problems with folders not populated, but that is now fine and she uses Firefox on an IMac, same OS with no problem.
Hmmm.
Tom
Consider taking your questions over to AOL and its forums.
Start a new topic or ask questions in the open forum.
