When working in a secured location - some place that uses HTTPS inspection for the firewall, possibly application level filtering, etc - how do you get Group Chat to work correctly in Skype?
Adding skype.com / pipe.skype.com to the HTTPS inspection bypass list gets the main chat, VoIP and video to function, however it doesn't do anything to resolve the 'spinning wheel' for group chat.
Since Microsoft purchased Skype they made a number of updates to how several parts of the application work. Most notably this has to do with the sign on / microsoft account functionality.
After a prolonged session with psexec a number of different sites under the following subdomains became evident as hanging when attempting to send a message.
Adding these to the HTTPS inspection bypass list (with appropriate wildcards depending on the firewall vendor) takes care of the issue.
Also depending on the vendor and the policies in place these specific URLs may be blocked by category, as they are used for instant messaging.