To address this problem, run ZMAdmin and look at the configuration for your HTTP Server(s). There are 2 settings which are likely involved: Send Http Version, and Send Http Colon. Try reversing the settings, refreshing your web application, and retesting.

As of 25-Nov-2007, valid settings were: version true, colon false.

It is often asked, why do we ship WebHub with seemingly-wrong settings for popular end-user systems (in this case, the Apple iMac). The answer is that in the years since 1995, the end-user requirements have changed, in some cases reversing themselves. There we allow the configuration to be controlled at any time as explained above. Perhaps by 2020 all the http servers and clients will finally agree on how they want the http prologue to appear, and their tolerance for errors.

Note: Safari from 2005 on an iBook laptop is able to view content from misconfigured web applications, but displays the http prologue as the first line of the site.

Reference: SendHttpColon property