Hello,
Since the remote server is in a DMZ, please open ports on the firewal so that the media server and the remote server can communicate between each other.
This you can do in Backup Exec - Tools - Options - Network - 'Media server port range' & 'Remote server port range'. For the media server you can open 50 ports and for the remote server 25 ports. Also the port 10000 should be open on both the servers for them to communicate between each other.
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