When HughesNet was our primary Internet connection (fulltime RVers then), I stopped using their DNS servers because of issues that occurred from time to time. I instead configured my router to use OpenDNS (I think that was it, but I lost the old networking posts, so I'm not certain about that).
That was much more reliable.
I'm not sure what setting DNS server to 9999 would do .... probably use some default instead of the DNS server from the connected Internet connection.
HughesNet mobile dealer and installer