Messages suddenly won't work
Hi, I'm having problems with Messages on my iMac, while it works fine on my iPhone.
--- It suddenly doesn't work: When I launch it from the Doc is shows no window, or a small blank window. Repeatedly clicking the icon in the doc, it then shows the small window saying "No Conversation Selected" while the Preferences is grayed out.
--- Under My Status it shows Offline. When I change it to Available (or any other status), I get a "talk.google.com Password" request, with one of my Gmail addresses that I must have assigned to Messages. I KEEP TYPING THE RIGHT PASSWORD (I double-checked it signing in to that Gmail account) — YET IT WON'T TAKE IT, it keeps asking for the password repeatedly.
--- I use 4 email accounts, 2 of which Gmail accounts. Not sure when/where I assigned one of those Gmail accounts to Messages, and I'm now baffled it won't recognize the password I'm using for that Gmail account.
--- On the iPhone (Settings > Messages> Send & Receive) I now have the 4 email addresses, just to be on the safe side. I also deselected and then selected again the iMessage button on the top. Nothing works.
Any suggestions?... Thanks in advance!
iMac, OS X Yosemite (10.10.5), 27" 24gb RAM Late 2012