When sending client credentials to authenticated WCF service in MonoDevelop, the domain portion of the username is being ignored in OSX. This is on a Windows domain. For example:
In windows, when entering the user as 'usa\ccisat1cjc' MonoDevelop will send the credentials as-is, using usa as the domain name. In OSX the credentials are being sent as 'cco.clearchannel.com\usa\ccisat1cjc', ignoring the domain override of usa and simply appending the strings. This can be verified using wireshark.
Original issue was been submitted by Chuck Condron (chuckcondron @ clearchannel.com)
Issue solution may be similar to this: https://bugzilla.xamarin.com/show_bug.cgi?id=2415