Yeah, I just saw it in Waterfox. See what happens with this --> https://login.xfinity.com/login I'm able to sign in and just paid my bill. see screenshot What address is your bookmark pointing to?

If you use a bookmark to access a specific page then instead navigate to this page starting with the main page or with the sign in page in case there is a problem with this bookmark.

I was having the same issue with one and only one website. At the suggestion of the website owner, I went to Firefox settings and unchecked the box listed under certificates, "Query OCSP responder servers to confirm the validity of certificates". Issue solved.

You shouldn't disable OCSP as this is a security measure. Websites should have their security up to date and have a valid certificate. You can check the server to see whether they already have fixed this.:

• https://certificate.revocationcheck.com/