Normally what causes such problems is lost of data while the client to server communication... It is caused by a high ping/latency of your connection with the server, and when during the communication to the server if there is any sort of important lost of data the server just returns the "rejected from server" message.
I haven't experienced this issue myself even when my ping is as high as 200ms -300ms, I'm not sure what might be causing the problem. Sometimes it could be that your router just needs a restart, or some problem with your ISP.
I don't have a concrete solution for this, so I will leave this topic opened to see if any other GM or player has a possible concrete cause to this sort of issue.
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SInce there was no other feedback from other players at all, I will close this topic and consider it as solved. If you encounter this kind of problem again feel free to make a new topic, we will do our best to look for a solution.