OSX Remote Desktop Client Fails With ‘404 not found’

I recently had a strange issue with the OSX version of Remote Desktop Client connecting to a RDWeb server over the internet. The client kept reporting “The gateway failed to connect with message 404 not found”. Digging into the logs under the about box I found the following: [2014-Jul-18 11:23:53] RDP (0): —– BEGIN ACTIVE.