You have been blocked from the manager by an administrator

A user that does not have manager access is getting this error when trying to login in and I’m not sure why. They are a member of a user group with front end access only.

When you edit a user, there is a checkbox “Blocked”. This checkbox is most likely ticked () for this user.

The error message is probably just misleading, because the same processor is used to log in a user in the front-end and the manager.

Another (less likely) possibility is that the user is going to the Manager URL and trying to log in with their front-end credentials.