I don't know a whole lot about the server side of things, but from my experience Insta-kicks are a result of one of two issues. 1) anti-cheat software not downloaded properly or accidentally deleted, or 2) The game bugging out because some downloads might be corrupted.
To fix the first issue go to this link, and it will help you identify and fix if the problem is the anti-cheat. https://offworldindustries.zendesk.com/hc/en-us/articles/221442887-Easy-Anti-Cheat-Errors
For the second issue you can go into steam and verify your files. Worst case scenario just re-install the game. Re-installing will insure everything is re-downloaded properly. Finally if no of that works I find time fixes all problems. Some issues are just on their side of things and get fixed over time without you doing anything.
Again i have little to no knowledge, but I hope this can help you in fix your problem.