Reasons for non - subscription

1 Your orchestration is not started, which in your case it should be since
you are waiting for the second message, but check to make sure you have an
active instance in HAT

2 The message properties you are correlating on are not getting promoted
when the second message is being received, or the property values are
missing in that document. Check the message context associated with the
routing failure message in HAT to check the properties.

3 Your correlation is not getting properly initialized.  Check this with the
handy subscrciption viewer found in the SDK folder of BizTalk.  After your
orchestration starts and sends a message, load up the subscription viewer
and you should see a subscription of type XLANG with the correct properties
displayed at the bottom when you highlight its row.  Check these values
agains the message context as mentioned in #2.