Hey Britgirl,
More info for ya. I completely removed 8.2.3 from the Mint 21 box, rebooted, then installed 7.9.2 that I had. Low and behold, works as it should and I’m able to get to all the boxes. So I do an update to 8.3.2 from the app, restart, and she’s back to where I was, the mint 21 box won’t connect and just closes the windows again. It did do another core dump and it looks the same as I had sent ya!