I branched this off into its own discussion as it doesn't involve the CASO option of the forum query you posted on...
You'll get this message if the connection to the BEDB is lost for whatever reason. Check your AV and make sure it isn't blocking any BE services, and if need be, put in an exclusion for them.
Also run BEutility and choose the option to repair the BEDB. If need be, move your default maintenance window for the BEDB from 4AM to earlier or later in order to rule this out as the cause.
Do you have your backup exec database on a local instance of SQl or is it on some remote SQL server ?
If its on remote SQL check if you have good connectivity between the media server and SQL server.
Not sure if it has to do something with the enhance network security in backup exec r3
OK...so do the following:
1. Check that your AV isn't blocking the BE services, and if so, put in exclusions for it.
2. Make sure that the correct firewall ports are open on your server (if you run a firewall) to allow communication to run normally. Check the TN below:
3. Run BEutility.exe and do a repair of the BEDB.