Plastic says "Invalid credentials, username or password are not valid." on editor restart

Plastic SCM is behaving weirdly in one particular project: When I set up versioning through the Tools/Revision control settings then it works like in the other 4 projects (4.27, 5.2, 5.3). However in this one when the editor is restarted then it loses it and starts spitting this sort of messages on any version control activity:

Warning: RunCommand: 'fileinfo --format="{RevisionChangeset};{RevisionHeadChangeset};{RepSpec};{LockedBy};{LockedWhere}" "C:/Users/****/wkspaces/Project****/Config/DefaultEngine.ini"' (in 0.042s) output (58 chars): Invalid credentials, username or password are not valid.

Error: FPlasticUpdateStatusWorker(ErrorMessages.Num()=1) => checkconnection

If I then open the version control config panel, set it to “None” and instantly back to “Plastic” and accept the settings then it works again until I restart the editor.

Windows 10 (22H2), Unreal 5.3.2, Unity DevOps 11.0.16.8289