Hi roguemodel, did you notice any visible difference in the payment process, such as a CAPTCHA or other extra verification that was missing on Firefox? Or was nothing noticeably different?

If it wasn't something obvious, this becomes a difficult question to answer. It is possible for add-ons, privacy features, and privacy settings to affect the information that is passed to and among websites during a payment transaction which may cause the receiving site not to trust the request or to view it as suspicious.

Since you can't just make a dozen purchases to test various combinations of settings and add-ons, it may not be practical to troubleshoot this problem in detail. But you could at some point test in Firefox's Safe Mode. In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any difference?

Hi, I actually used Paypal through firefox and they could not figure it out. I also just tried to pay my Ebay bill and i could not get two cards to go through using firefox, but had no problem using IE. It was funny that Mastercard told me to use IE. Even if I used the secondary verification provided by my bank (mastercard securecode) the issue did not go away.

If you visit my test page and look at the HTTP headers of the request, does anything look off? (If you click through this web page instead of from your email, the Referring Page should be included.)

https://www.jeffersonscher.com/res/jstest.php

You can check the service provider associated with your IP address on this site, if you're in North America:

https://www.arin.net/

Either the same address will be auto-detected and listed by the site on the top line, or you can paste the address detected by my site into the search box on the top right. Just to confirm it's your real service provider.

Try to enable third-party cookies and make sure that you do not block cookies.

• Options/Preferences -> Privacy -> Firefox will: "Use custom settings for history"

• https://support.mozilla.org/kb/Options+window+-+Privacy+panel

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• Do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

If you use Private Browsing mode then try the regular mode.

Thanks very much everyone, 3 bar was the issue. I appreciate it!