I just tried using Vivaldi and Firefox, and I got to the website with only a slight delay. Try using a different browser, or just clear cache/history in whatever one you are using.
I can't connect to musicbrainz.org over Comcast. I've restarted everything, flushed my DNS cache, but nothing is working. I can get it fine tethering to my phone and using AT&T, but I don't want to use up all my data.
Perhaps posting the output of a traceroute to the site will reveal where the blockage is ?