I see that error occasionally, but very seldom. Usually seems to only be when I try to enter the game with multiple clients simultaneously though. I don't recall seeing it when I log each into the game with clients staggered at least a few seconds. YMMV.
I started my essence rules at a total rating of >=30 and damage >=10 and damage resist >=10 for the lower level ones, then moved up the reqs as I acquired better ones. It really wasn't too hard to find plenty meeting those reqs.
For me, the launcher is leaving the game_nnnn.txt files even after hours of the clients being logged out. That is causing the launch button to not work until the launcher is restarted (which deletes the txt files).
I'm seeing an issue with 18.104.22.168; when you exit an account it sometimes seems to think that client is still logged in until I close the launcher and reopen it. The Launch button will highlight, but it will not attempt to open the account when you click it. Of course it doesn't seem to be reproducibl...