Have you tried another DNS?
More at https://www.howtogeek.com/167533/the-ultimate-guide-to-changing-your-dns-server/
The only way I can load Disqus with a page that uses Disqus for it's comment section is to flush the DNS, then the page loads fine a new window. But upon accessing the web page a successive time the Disqus comment section does not load, unless I close the page, flush the DNS again and reload the page. This problem is occurring with FF 66.0.2 (64-bit). In addition, when I return to the page after closing the FF's built-in Narrator, I have to flush the DNS and access the page in a new window all over again. One of the pages I am experiencing this problem is https://www.newsbusters.org/blogs/nb/kristine-marsh/2019/04/05/daily-show-mocks-sanders-doing-fnc-town-hall-not-legitimate-news, though the problem occurs with other web sites as well with the exception of https://www.dailysignal.com which loads the Disqus Comments sections just fine.
I have tried System Restore, sfc /scannow, reinstalling FF - even installing earlier versions of FF. I have also tried updating and running full scans with Windows Defender, Malwarebytes, SuperAntiSpyware, Disc Cleanup, CCleaner and adding https://disqus.com to Trusted Sites in Internet Options, but non of these have been of any help.
I am using RAMDisk from http://corporate.dataram.com. I have tried turning the RAMDisk off but this too has had no effect.
I had been experiencing the same problem with IE 11, but I no longer experience it after having flushed the DNS.
I am also using Windows 10 Home (64-bit) with a 64-bit machine and all OEM, MS and Windows updates.
Would appreciate any help anyone could offer.