[MC-88963] Two Players Cannot Join Server

Whenever two players are on my server at the same time, one of them get kicked, and get this error message; https://i.gyazo.com/ca3f248c644bb1d66ce1ea3d1bc85413.png

I fixed the problem by destroying a good amount of nether portals.

Attachments

Did you create the world in this snapshot or in some previous ?

1.8.6 If I remember correctly.

Ok, but did you load the world in previous snapshots ? If yes, which ?

I created the world in the second 1.9 snapshot, and loaded it in all of them.

Some early and later snapshots broke the world.

It worked fine when I download the world and ran it on LAN.