Starting with version 2.3.6 I got timed out shortly after logging in to the server. I have no machines or mob farms, all I have built is a slab platform with one tree. I cannot log in again after that and the server isn't responding anymore. There are no errors or crash reports.
I just updated to 2.3.6 Hotfix and the same thing happens.
It always happens when I build a slab walkway (lower slabs). The only way I can login to the server (after restart) and not get timed out is if I edit my players position to my islands spawn coordinates. After that, when I build a walkway again with lower slabs I get timed out within a few seconds, and when I try to log in I find myself falling in to the void and the server times out and becomes unresponsive.
The only message I've ever received (only once in all my testing trying to fix this issue) was this:
24.08 10:31:12 [Server] INFO Aug 24, 2017 10:31:12 AM io.netty.util.ResourceLeakDetector reportUntracedLeak 24.08 10:31:12 [Server] INFO SEVERE: LEAK: ByteBuf.release() was not called before it's garbage-collected. Enable advanced leak reporting to find out where the leak occurred. To enable advanced leak reporting, specify the JVM option '-Dio.netty.leakDetection.level=advanced' or call ResourceLeakDetector.setLevel() See http://netty.io/wiki/reference-counted-objects.html for more information.