Steam Auth Ticket has been cancelled

[spikeman14]

I am currently developing a gamemode, and I always get the error message

Steam Auth Ticket has been cancelled

Garrysmod crashes with no error and no dump file.

I created a client-side console log and that shows nothing but a blank line when I crash.

I found some pre-historic forum post about the same error and it was to do with ULX. I don't have ULX installed on either client or server!

What is this about? The gamemode is no where near complex enough for it to be a coding issue. Is there a function to handle steam auth tickets that I have missed?

Please help facepunch community, you are my only hope.. *DAA, DARRRR. DA DA DA DARRRR DARRRRR*

Here is my console log

Initializing Awesomium..No Kinect SDK
Lua JIT is DISABLED!
Unknown command "cl_thirdperson"
Unknown command "hud_showemptyweaponslots"
Unknown command "sv_backspeed"
Not playing a local game.
Changing gamemode to When Props Attack (whenpropsattack)
Map file wasn't found, copying it from addon..
PREP OK
Map file wasn't found, copying it from addon..
Failed, using default cubemap 'engine/defaultcubemap'
Failed, using default cubemap 'engine/defaultcubemap'
Failed, using default cubemap 'engine/defaultcubemap'
Failed, using default cubemap 'engine/defaultcubemap'
Error, bad server command lua_error_url ''
Lua JIT is DISABLED!
Wiremod Version 'Workshop' loaded
[AddCSLuaFile] Couldn't find 'weapons/gmod_tool/shared.lua' (<nowhere>)
Couldn't include file 'includes\modules\glon.lua' (File not found) (<nowhere>)
Skipping disabled E2 extension 'propcore'. To enable, run 'wire_expression2_extension_enable propcore'
Skipping disabled E2 extension 'remoteupload'. To enable, run 'wire_expression2_extension_enable remoteupload'
Skipping disabled E2 extension 'wiring'. To enable, run 'wire_expression2_extension_enable wiring'
TEST [maps/gm_flatgrass_classic.bsp][maps/gm_flatgrass_classic.bsp]
FOUND IN ADDON [110287733]
TEST [maps/gm_flatgrass_classic.png][maps/gm_flatgrass_classic.bsp]
TEST [maps/ttt_crystalmaze.bsp][maps/gm_flatgrass_classic.bsp]
Making workshop map available for client download
Using map cycle file 'mapcycle.txt'.  ('cfg/mapcycle.txt' was not found.)
Nav File is wrong or something (1)
Garry's Mod
http://loading.garrysmod.com/
whenpropsattack
gm_flatgrass_classic
1
76561197993715322
Requesting 5 lua files from the server
clientside lua startup!
Lua JIT is DISABLED!
Requesting texture value from var "$dummyvar" which is not a texture value (material: NULL material)
Compact freed 577536 bytes
Player:Erected Member is authorised
Redownloading all lightmaps
Erected Member was killed by jumper
Warning: killicon not found 'jumper'
Erected Member was killed by jumper
Erected Member was killed by jumper