There is some issue connected with GG transport. Earlier version of GG clients haven't got functionality to use account login with numbers above 17mln (probably limit connected with 2^24 = 16777216), these numbers were unavailable. But since new version which removed that limit was released last year, these account numbers are possible to use and there is a problem with communication between new and older clients when there is a person with account number bigger than 17mln. Kraken Gateway also is vulnerable and has a problem with communicating to that kind of users like the older native clients.
Windows Server 2003