Symptoms

When configuring "Out of Office", the spinner does not stop after searching for the target OOF user.
 

Diagnoses

This was because of IE browser settings. The workspace URL was not in the "trusted sites zone" and the proxy settings were incorrect.
 

Resolution

- We added the workspace URL to the "trusted sites zone" (http://help.k2.com/kb001578) - And we correctly configuring the browser proxy settings and this did the trick. (In this case, there was not proxy, so we unchecked/"un-configured" all relevant proxy settings in the browser.)