-> Type about:config in the address bar and press Enter

• When you see a Warning, click I'll be careful, I promise button
• In the Filter bar, type network.http.sendRefererHeader
• If the preference network.http.sendRefererHeader appears in BOLD text, right-click it and choose Reset

Check and tell if its working.

I got to the preference screen, but my reset option was 'grayed' out?

Options I got with right-click was:

- Modify (in bold) - Copy - Copy Name - Copy Value - New - Reset - 'grayed out' unable to select

Clear Cookies & Cache

• https://support.mozilla.com/en-US/kb/Template:clearCookiesCache

Clear the Network Cache

• https://support.mozilla.com/en-US/kb/How%20to%20clear%20the%20cache#w_clear-the-cache

Troubleshooting extensions and themes

• https://support.mozilla.com/en-US/kb/Troubleshooting%20extensions%20and%20themes

Check and tell if its working.

I got this same thing. The next response is just way to confusing and technical for me. Is there an easy fix, or will Mozilla fix this?

Sorry, I got the same problem as AnjieJ

CSRF involves cookies (at least on this forum) to verify that the form that you send was supplied by the server.
Make sure that you allow cookies from the involved sites.

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

• http://kb.mozillazine.org/Cookies

Thank you for the response. I followed your instructions and removed all cookies and I still get the Forbidden (403) CSRF message.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

You can try to check with the the Live HTTP Headers extension to see if that cookie is send.

• https://addons.mozilla.org/firefox/addon/live-http-headers/

Again thank you but no go. I will just use a different browser when I want to use Pinterest.