Horde Webmail and Broken URL

[LAM09]

Hi, I am having a confusing issue with horde webmail. I have switched this on for all the domains in the VPS, and I can see the webmail icon is in colour (not greyed out) against all the email accounts related to the domains. However the link to webmail.mydomain.com is not reachable for one website.

Can anyone think of why this could be?

 

[LAM09]

Nevermind - Fixed it. The nameservers were not set up correctly