Ducksdns addon can't get to

I just changed internet providers. ATT to Spectrum. They provided a router. I opened port 8123. Have been using duckdns to get to my home assistant which is running on a a ubuntu 18.04 server running docker. When I try to start the ducksdns container I get the following error.

ERROR: Problem connecting to server (get for; curl returned with 6)

I have searched the forums and found discussions pertaining to the DNS server used by some isp’s. I did install resolv.conf with dns address’s, but still get the same error.

I suspect the problem is in the Specturm router so ordered a new router that I can configure myself.

I anyone knows a way to resolve this without installing a new router I would appreciate help.