It looks like there may be a firewall rule in place for TCP 4505-4506. Can you please check again to ensure the problem has persisted, by trying to activate your license? If the problem persists please run the following commands and reply with the output.
nc -u -v vsm-us-51.virl.info 4505-4506
nc -vz vsm-us-51.virl.info 4505-4506
The difference here is that we are attempting a connection using UDP versus what the script checks for; which is, a simple probe on TCP 4505-4506.
*Please try this with each US salt master. For the first command , you'll need to press ‘ctrl+c’ to end a successful connection.
Cisco Learning Network