I downloaded and installed Ultima Online Enhanced, which is the Stygian Abyss client renamed. It installed and updated flawlessly, and (after installing DirectX) I was able to log in to my character and look around.
Then I logged out to switch characters. Ever since, I've been getting "Connection Lost" immediately upon selecting a shard. If it follows the pattern I saw back in early 2017, about one time in 100 will work now.
The last time I tried Crossover Mac (9 months ago) I had the same problem. Same with a previous time, though I can't remember when that was. Any ideas?
Edit: I am still able to occasionally get past this. I think the odds are slimmer than 1/100, though.