I am mid way through migrating from Exchange 2007 to 2013. I have been following the instructions on Step-by-Step Exchange 2007 to 2013 Migration (it would not let me link it unverified). I have had to undo some of it in order to keep email flowing for the organization.
From the 2013 ECP, I cannot see the Mailbox Databases residing on the 2007 server. I successfully migrated a single mailbox to the 2013 server. If I have the 2013 server as the internet facing server as per the instructions, I can access the migrated mailbox without any issue via OWA and Outlook. I cannot access any mailboxes on the 2007 server in any way though.
With the 2007 server as internet facing, I can access every mailbox except for the migrated one. There appears to be a disconnect between the servers that is blocking communication.
From my understanding, I should be able to have the 2013 server set up to take over and all mailboxes should be accessible through that server. I have already tried checking some of the answers regarding the public folders (I have not even started to tackle that yet), but none of it seems to apply. I can see the databases from both servers through the management shell with no errors. Other than being unable to access mailboxes on the secondary server regardless of which is primary, I have not seen any errors.
Any help or suggestions would be appreciated.