System activation will not work

FreePBX 12.

I’m trying to activate our system to get the license for Sysadmin Pro, but I’m getting an error saying

Couldn't resolve host ''

Pinging that from a command line works fine, however the host does not respond to any pings. Going to that address in a web browser results in a nearly empty XML document, so obviously the host is up, responding, and I can get to it from our phone system. Not sure why that isn’t working.

I’d check the contents of /etc/resolv.conf on the FreePBX machine, and see if that has possibly become corrupt?

Definitely nothing to do with DNS. If resolv.conf were having issues, I wouldn’t be able to ping that host from the CLI. That’s why this is a strange error being that is undoubtedly resolvable.

I was able to get this to work by adding and its IP address to the hosts file on the phone system. Very strange since I got the IP for from the CLI on the phone system.

modify /etc/resolv.conf as indicated

nameserver # mandatory
nameserver # your first préfered DNS
nameserver # your second prefered DNS