Sorry for the late response! Basically the message An existing connection was forcibly closed by the remote host means that the other side (in this case the client) closed the connection unexpectedly. It's a very general error message and doesn't provide any information about what went wrong. Possible reasons why this error occurs:
- There is a connection issue between the client and the server. It could be either the client connection or the server connection which causes trouble
- The client sends malformed data to the server, either caused by other programs (security programs) or connection issue
It's also possible that there is a completely different issue which isn't even related to the networking. If the client gets stuck in the loading screen, and cancels the loading process (or quits the game), this could also result in this error message.
Another situation where this error can occur is when a client simply disconnects. Since we use several channels (and every channel runs in a separate thread), there is a chance that this error shows up when the client disconnects while the server still sends/receive data to/from the client. Basically this error is harmless and can be ignored in this case (if we want to avoid it, it would be necessary to synchronize the traffic, which would have a negative impact on performance - so there is really no reason to do that).
A clientside log will likely provide more information about what's going on. If only few players run into this issue, this might be a clientside issue, if the majority of players experience this problem, it might be a serverside thing.
@ViralGamer: What happened exactly in your case? Did you only see the error message in the logs without actually having any noticeable problems, or do you get stuck in the loading screen (or something like that)?