I receive this error after I log in with my character. He previosly loged out while standing in Zereth Mortis.

AdventureGuideLookouts ERROR: instancelD is nil. Please report following values at https://github.com/Meivyn/AdventureGuideLockouts/issues
AdventureGuideLockouts DEBUG:
instanceMatch="2481",
instanceLink="Jcffff8000|Hinstancelock:Player-1379-0AB5BC68:2481:14:1211|h[Sepulcher of the First Ones]|h|r"

That should be solved if you update to latest version.

Yes, it seems that WowUp app was not providing the latest version.
I downloaded it manually from Curse and it is fine now, thanks!