We have Exchange 2010 and 2013 SP1 running in the same environment for migration purposes. The server is 2012 R2 and once we installed symantec endpoint protection the migrated mailboxes no longer receive/send emails. After uninstalling SEP the problem is still there. The Exchange transport service will not start. After disabling all the receive connectors the service starts but cannot send mail. During migration the primary exchange (2010) relays mail to 2013 and 2013 relays mail back to 2010 to send. The connection between the two systems seems to be broken.
We have restored an older backup on the 2012 Exchange 2013 server and now the server is at 100% CPU useage. The services are all started but nothing is working.