VirtualDomain

This problem occurs when you have the RT in a virtual domain in apache. Check out your mailgate alias:

rt: "|/opt/rt3/bin/rt-mailgate --queue general --action correspond --url http://localhost/"
rt-comment: "|/opt/rt3/bin/rt-mailgate --queue general --action comment --url http://localhost/"

Eg. If you access your RT using helpdesk.example.com you need to change the localhost in the example above for helpdesk.example.com turn into:

rt: "|/opt/rt3/bin/rt-mailgate --queue general --action correspond --url http://helpdesk.example.com/"
rt-comment: "|/opt/rt3/bin/rt-mailgate --queue general --action comment --url http://helpdesk.example.com/"