A buddy and I try and play together but anytime we que for a warzone or anything in COD we end up disconnecting from each others lobbies. We had the same issue in the previous COD but used a third member to hoast parties.
For Call of Duty: Modern Warfare, Blizzard Support is only able to offer support for install, patch, connection issues to the Blizzard Application. For this issue, please contact Activision Support or refer to the Modern Warfare forums.