A similar issue is occurring on my 15w37a server. Pretty annoying issue... the server seems stable if one person is online but as soon as another player joins - the server goes haywire and lists the following error in the console:
[Netty Server IO #6/ERROR]: io.netty.util.IllegalReferenceCountException: refCnt: 0
The second person that joins also cannot be seen by the player who was already in the server. The second person is completely invisible to the first player but can still interact with the world. Sometimes the server will stay up for up to a minute after the error and then kick any players on the server out, afterwards closing itself.
Also, If you are playing on the server and a second person joins the server and spawns far away from you, teleporting to the second person's location will crash the server instantly.
Jessica Terrano
A similar issue is occurring on my 15w37a server. Pretty annoying issue... the server seems stable if one person is online but as soon as another player joins - the server goes haywire and lists the following error in the console:
The second person that joins also cannot be seen by the player who was already in the server. The second person is completely invisible to the first player but can still interact with the world. Sometimes the server will stay up for up to a minute after the error and then kick any players on the server out, afterwards closing itself.
Also, If you are playing on the server and a second person joins the server and spawns far away from you, teleporting to the second person's location will crash the server instantly.
Hopefully this gets resolved!