hi,
with Frontend v2.2.6r1 i get a lot of this error message:

"Operation cannot be performed due to unauthorized request"

At a refresh helps, but in most cases you must make a re-login.
I see this mainly in chrome latest version but not as often in the other Web browsers. In the logfile from the Aapche found nothing suspicious. Perhaps important as info, the Frontend is accessible via port 8080.