When initiating a conversation from an account on my Jabber server (I have tried this with openfire and jabberd-2.0) to a gmail account, I receive a Code 503 error. However, when initiating a conversation from a gmail account to said account on my server, it goes through. This does not change if a previous conversation had already succeeded, and is not a s2s connection issue - my logs show a successful server to server connection. The only thing I notice that might be causing this is the fact that neither account is subscribed to the other, but this has never been an issue before with other Jabber servers - I have held conversations between accounts not subscribed to each other on myriad corporate and personal Jabber servers before. Also the fact that it works gmail->external makes me think this is not the issue.

Can anyone shed some light on what the issue might be here?