I have added an Exchange 2010 server to our environment. All mail is routing through our Exchange 2007 server.
Users on 2007 can send to users on 2007 but not to 2010
Users on 2010 can send to users on 2010 but not to 2007
Users on 2007 can send and receive external email
Users on 2010 can send external email but not receive
I know this is a connector issue but not quite sure what connectors I need and permissions to go on them.