Hi

What is the address of the website that you are trying to view?

One example that fails: https://www.realfastspanish.com/grammar/the-spanish-future-tense?utm_source=RFS+Email&utm_medium=email&utm_campaign=future-uses%3Fomhide%3Dtrue&vgo_ee=IU0yBw%2FK4nVhri3yk8%2FqNAGhJYeo3k3ZQ5EjZ7gVw5ve92uiEQ%3D%3D%3APXKZ%2FSJ2OH%2FaJNZ91TXiU%2B3HXzsWDQ4N

Other links to https://realfastspanish.com/ also generate 403 error.

Hi

This does not appear to be an issue with Firefox. Looking at the website registration details, it appears that there was a change made to the website, possibly by the website admistrators, at 0743 (UTC time) today.

I get the same error when trying to load the website. 0000 Fri Oct 13 UTC.

Work around for my user is Edge. No idea what is up with the website. It does seem to have some certificate issues, no idea if that is part of the problem.

Based on your above reply, I tried with an Edge user agent in Firefox and that works, so it looks that they have a problem with the Firefox user agent. Further testing shows that this is likely a problem with the version in Firefox/xxx It works with Firefox/60.0 til Firefox/99.0 , but over 100.0 it fails. You can contact the website and ask them to update their browser sniffing code to support a three-digit Firefox version. This user agent works for me:

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/99.0

A similar question about the same user agent range :

• /questions/1424393 I have received 505 Bad Gateway and FORBIDDEN

See also

https://support.mozilla.org/en-US/kb/difficulties-opening-or-using-website-firefox-100

^: Note that the "network.http.useragent.forceVersion" no longer is supported in 116+.

• 1837343 - Remove the "network.http.useragent.forceVersion" pref [116]