Webmail - CGI Error

[Leevis]

Hey all, we've never used webmail with Plesk but would like to start. When I go to open webmail, I get the following:

CGI Error

The specified CGI application misbehaved by not returning a complete set of HTTP headers.

I've found a couple of posts on this forum about the same issue, but none of them provided a fix or tips on troubleshooting. Any help would be greatly appreciated.

Thanks in advance.