Is anyone else seeing this or is it just me? I installed Messages Beta the day after it came out. That was Friday. It worked perfectly (including message syncing with iPhone) for all of Friday and Saturday. Then on Sunday, suddenly it stopped working. Suddenly, I get the red circle with an exclamation mark for every message I try to send. When I click the mark OR the message, I get the error in the attached image. Back on Sunday I uninstalled and reinstalled Messages Beta. After that it worked great again. Until just now. Same thing as before. Just me or is this a thing that others are seeing? I know it's beta and I know hiccups are to be expected, but it's odd that it would work great for a while, then fail completely.