Thanks for your reply!
This is on Windows, I made a domain account and gave it the Logon as a service User Right and also NTFS permissions on the PasswordState directory.
But it is unable to start. When I make the account local admin, everything is fine.
So apparently there are some more permissions required, but I can not find anything in the manual.
The default is running it as SYSTEM, which we don't want to do because of security considerations.