[0.13.5] Server cannot handle more than 3 players

[Regallion]

I am currently running a headless server, in a 24/7 mode.
Recently, however i lost the ability to handle more than3 players at once.
(I do not consider <server> to be one of the players, although if you count him, it would be 4)
Here's the log for the server.
https://drive.google.com/open?id=0B5731 ... GVISnlCa2c

Basically once the 4th person joins it starts doing the heartbeat-drop indefinitely. To the players it appears as if the game hanged.
If you need anything else such as the savefile or the modpack, do say.
And yes, the entire log is relevant.
Oh and the server-settings referenced are only to disable user validation and set the server to hidden - there are no other changes to the example

[Regallion]

An additional problem - sometimes, when a peer quits, the server ALSO goes into an infnite heartbeat loop. That one isn't fun. From quizzing the players it seems that happens when they quit witht the red X as opposed to something more normal.

[Regallion]

I have performed some additional testing on the issue and got the following results:
12.35 clean: no issue whatsoever
13.4 modded : max server+3 players, adding another causes the aforementioned problem
13.5 modded: same as 13.4
13.5 clean install: same as 13.4
The quit loop issue is also present in all 13 versions.

[Regallion]

Still a thing in 13.6

[Regallion]

For the quit-problem issue.
It seems that if 1 player quits, when there are other players on the server, the game can hang more or less indefinitely. However if EVERYONE force-closes their clients after that, then the server will eventually process the whole dropping people part, and become unstuck. Could it be some sort of a conflict between synchronizations?

[TyphoonNL]

the problem is still there in 0.13.9

[nuhll]

Seems to crash not more (some mods seems to have updated).

BUT i cant place the chest for robots...

[kovarex]

As most of the multiplayer has been rewritten for 0.14, I will move this to resolved.