Getting error "User is not allowed to view the specified configuration" (4300474)

After creating Viewers Group and assign Group to default Published configuration, when a user of the Viewer group tries to login to Metadata Explorer get error

a) Metadata Explorer UI is Published configuration specific. Make sure there are models in Published Configuration. Please verify existence of contents in Published Configuration by checking in Metadata Manager 

b) make sure there is no specific security setting restriction on the Model itself under repository panel

If you have any users set under Viewer, this means there are restrictions for Viewer on model, the above setting only allows abc, maggie user can view the model in Published configuration. Please set to blank ( default). So everyone can access the Published Configuration