Exchange 2013 running on server 2008 r2 enterprise. Coexistence environment with exchange 2007 environment but the mailboxes in question are on 2013.
Clients are getting delays on emails by hours.
No evidence on the firewall (external device) that the emails in question are hitting the network.
Had an email sent to my exchange server and CC'd to a hotmail email account. The hotmail account got the email instantly. The email did have a small excel attachment.
Thanks