Whenever players open their default map, they get kicked with the following error that pops up in red text on their screen while in-server (note: I have no map plugins installed like LustyMap or the like) :

NullReferenceException: Object reference not set to an instance of an object.
UIMapVendingMachineMarker.UpdateDisplayName (System.String newName, ProtoBuf.VendingMachine+SellOrderContainer sellOrderContainer) (at <00000000000000000000000000000000>:0)
VendingMachineMapMarker.SetupUIMarker (UnityEngine.GameObject marker) (at <00000000000000000000000000000000>:0)
MapView.SetupMarkers () (at <00000000000000000000000000000000>:0)
MapView.MarkersDirty () (at <00000000000000000000000000000000>:0)
MapInterface.ForceOpen (System.Boolean open) (at <00000000000000000000000000000000>:0)
MapInterface.SetOpen (System.Boolean open) (at <00000000000000000000000000000000>:0)
BasePlayer.ClientInput (InputState state) (at <00000000000000000000000000000000>:0)
BasePlayer.ClientUpdateLocalPlayer () (at <00000000000000000000000000000000>:0)
BasePlayer.ClientCycle (System.Single deltaTime) (at <00000000000000000000000000000000>:0)
Client.Update () (at <00000000000000000000000000000000>:0)​

This started to happen after yesterday's Halloween update and I only see it on my server. Does anyone know from the posted error code if a plugin is causing it? If so, which plugin?

 

If there getting a RED error and then crash to launcher then they need to verify there game files. That would be something via the client and as far as I know nothing you as the server owner can do about it.

Hello Razor, thanks for your answer.
A few players already tried that, but the issue persists.
Additional information:

• I did have vending manager installed and have since removed it. I removed its data files yesterday and restarted the server but that phantom vending machine is still there and they still get kicked.
  
  • From someone in a discord:
    
    • I had something similar a while ago. It was a Vending plug-in that caused the problem. The plug-in (sorry, I don't remember the exact one) was used to set up a vending machine as a bottomless resource exchange because it was missing from a custom map we were using. When we changed the map at the following wipe, it was expecting to see a vending machine at a specific location together with its configuration and threw all sorts of errors because it no longer existed.
  • This has not worked.
• When a player dies, they get kicked and get insta-kicked from the server when they try to rejoin. When i died, i saw similar red text in the respawn screen.
• I will try to wipe the server and update this thread with an update.
• Multiple players including myself have observed that the server behaves like it is the first time they have joined every time they join the server.
  • Loads everything from scratch
  • Plugins still recognize that they are a returning player.

Hello, this problem is due to the complement of private Clans. That is, not the one found here for free. Update your add-on and you will stop having this problem.

Ah ok, thank you!
I wiped the server, which fixed it. I tried restoring the old .sav file, and the issue popped up again, so it appears to be that the issue was with the corrupted .sav file. I believe this had something to do with residual VendingManager files in the oxide data folder causing some old vending machines to remain where they were not on the in-game map.