This is an error that is happening in the Lightspeed shop. (not actually a BRM error)
When BRM talks to Lightspeed (e.g. to pull in customers and transactions) it must use one of your user's accounts on Lightspeed. This account is mapped to your BRM user. It must be active!
The exact message is "Employee can't login. Verify that it isn't locked out or archived"
If you are uncertain which employee id is linked to your BRM login, then check against that user account - and it will tell you which Lightspeed user ID it is linked to:
Settings > Users
