I am running and Exchange 2010 setup in a DAG. I have 8 servers. 2 Mail, Hub, CAS & Edge.
One of our edge servers has about 9500 messages backed up in Shadow Queues with the next hops being our hub servers.
Mail is flowing as I can send myself external e-mail messages and get them immediately.
Any idea what would cause shadow copies of e-mails to hang in the edge queue?