MAC OSX Yosemite (10.10) Connection Issue
All users that have updated to OSX Yosemite (10.10) or above and have our old Mac app installed (prior to 13/11/14) will need to remove the old version and download the new version via the Mac setup guide. The old version is not compatible with OS X Yosemite or above and will no longer be able to connect so updating resolves this problem.
PLEASE NOTE: You must remove the old version as per the new Mac OS X setup guide before downloading and installing the new app otherwise you will not be able to install the new version.