The following steps have worked on some customers environments:
1) Stop QC service;
2) Locate on hard drive file named Microsoft.WindowsAzure.ActiveDirectory.2013-11-08.dll;
3) Make backup copy of this DLL and delete original Microsoft.WindowsAzure.ActiveDirectory.2013-11-08.dll;
4) Restart QC service;
5) DLL will be re-generated by QC connector.
NOTE: during creation of the new DLL, the connector will need to download a new Schema from the url:
Please make sure there is no firewall rules that may prevent such connection.