Hi,
CC and scanners are separated, right?
Looks like CC cant resolve or access the symantec repository server.
What you can do:
Gui - Administration, Utilities, select your CC and nslookup swupdate.brightmail.com -> should get you some ips
SSH - open session to CC with support-user. "wget -p https://swupdate.brightmail.com/" -> should get you "200 OK"
Regards
Thomas