Set up a machine with Debian (possibly also happens with other distributions). I used Debian 9 for my own local testing, While I also got a server running Debian 7 where the same happens.
Run some mods (filler mod [[ https://feedback.bistudio.com/T117183 | found here]]) 1000 should do the job.
Make sure Battleye is running in server.cfg
BattlEye = 1;
battleyeLicense=1; // Possibly not needed
Start server running the mod(s) and using the config.
And join server and see that you will get stuck on a never ending loading screen trying to get into the lobby/mission select screen.
Now disable Battleye,
BattlEye = 0;
battleyeLicense=0; // Possibly not needed
Start server again same mods and edited settings.
Join server and now you will/should be able to join.