iMessage and Google Talk not working on macOS High Sierra (10.13)
I recently upgraded my computer to macOS 10.13 and found that my iMessage (in Messages.app) wasn’t working entirely and that Google Talk in the same app would only receive messages and not send.
Starting with the Google Talk issue, that’s an easy one. Apple has removed “official” support for Google Talk from Messages.app but they’ve clearly left the code in place that allows your old account to login, connect and actually receive messages, but helpfully added a dialog that says “Your message could not be sent. Support for the targeted service Google Talk has …