I've just installed a brand new installation of Zimbra NE:
OS: Ubuntu 8.04 Server
Zimbra: Network Edition 6.0.1 (GA 1816)

A paid license is installed.

The Admin interface works fine, I've added users/distribution lists.

When going to the Zimbra web interface though I get the following error message:
501 Not Implemented

The requested method is not implemented by this server.
The server status in the admin interface seems to indicate that all services are Ok (ticked).

Two things to note:
  • The machine is underspec'd (512 MB of ram), the machine used to work fine when running 5.0.10 - 5.0.19.
  • I'm using redirect mode for the web interface (switching back to mixed mode doesn't fix it though).

Any ideas where I should start my troubleshooting?
Any help is much appreciated.