Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

403 error Firefox only

  • 8 cavab
  • 4 have this problem
  • 1 view
  • Last reply by cor-el

more options

I am running Firefox 118.0.2 64 bit on windows 10 22H2. For one particular website I get a 403 error on Firefox, the site opens normally on Edge. I do not have any add ons or extensions that block websites. I have cleared cache and cookies and tried to open the site in troubleshooting mode, no luck. I have also disabled BitDefender, same results. Any suggestions are appreciated.

I am running Firefox 118.0.2 64 bit on windows 10 22H2. For one particular website I get a 403 error on Firefox, the site opens normally on Edge. I do not have any add ons or extensions that block websites. I have cleared cache and cookies and tried to open the site in troubleshooting mode, no luck. I have also disabled BitDefender, same results. Any suggestions are appreciated.

Chosen solution

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 :

Read this answer in context 👍 0

All Replies (8)

more options

Hi

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

more options
more options

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.

more options

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

Modified by Terry

more options

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.

more options

Seçilmiş Həll

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 :

Modified by cor-el

more options
more options

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

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