C7000-100NAS bot allowing access to 1 Website?

We have one of these routers on a Comcast Business account. The other day we lost the ability to connect to our externally hosted website.

Our local domain: "thisdomain.localhost" and the site is "thisdomain.com" - has worked for years. I can ping and tracert to the site but browsers timeout.

Is it possible Comcast chnaged something? I have a DNS forwarder entry to point the web address to the proper external IP. A nslookup shows a number of public IP6 addresses showing up which never did before prompting some network people to tell me this modem is leaking those addresses from Comcast. To make things worse, i can't login to the admin page (took this abanadoned account and nobody knows the login for the router.) And ideas to check? Thanks.