My server supports versions 1.7-1.12.2, the server itself however is based on spigot 1.12.2 - latest build. The problem that is occurring is exactly as explained in the title, players who attempt to join with the 1.8 (1.8 - 1.8.9) (vanilla or modded) client are kicked every time with either the following message: Code (Text): Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host or occasionally a timed out message. I've found that this issue is probably not due to a plugin since I've went through and disabled quite a few. I originally came to the conclusion that it was being caused by AACAdditionPro (Latest version) since after countless tests with it being uninstalled the issue stopped occurring. That was before I realized I was on a fairly old version, when I updated the addon to its latest version and reenabled the plugin, there was no evidence of the issue. However, after a few restarts later the issue once again continued with the same error. I uninstalled both the addon and then the anticheat (AAC) itself, however that resolved nothing. I've tried uninstalling countless plugins with no luck, however occasionally after perhaps a few other restarts the issue disappears for no apparent reason. Therefore there appears to be no pattern that I can notice so far with the issue. Perhaps someone may have a better clue as to what may be causing the issue.