Users cannot access quarantined messages (port 8081)

Hi,

My users cannot access their quarantined messages via the link sent to them by email.  This accesses via port 8081

This can be accessed on the server however.  I cannot telnet to server 8081 despite creating a port redirection in the firewall.  FW is a Draytek Vigor 2850.

Can anyone assist please?

Thanks