Running Zimbra 3.1.0 I get the following error in firefox when trying to print from the webUI :
Proxy Error
You don't have permission to access /zimbra/public/frameOpenerHelper.jsp on this server.
I get this error in IE:
You are not authorized to view this page
You might not have permission to view this directory or page using the credentials you supplied.

HTTP Error 403 - Forbidden
Internet Explorer
I can occasionally get it to work, but I'm not sure what makes the difference as it seems to randomly work (and I don't do anything to it between it working and not working). My catalina.out doesn't have anything in it and doesn't like it has been written to since tomcat was restarted at 4am.

Thanks for any ideas.