This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

Firefox unresponsive on financial data update on Barclaycard and TescoMobile.

  • 1 reply
  • 1 has this problem
  • 7 views
  • Last reply by FredMcD

more options

When updating data on financial or commercial websites, Firefox hangs. In the case of Tesco Mobile, when creating a new account and buying a SIM, after about 10 minutes of hanging, the screen changed with this message: "400 Bad Request. nginx/1.11.3". I input exactly the same Tesco Mobile data on Chrome and it updated with only a few seconds delay.

I use Windows 10 1803, McAfee Live Safe and Trusteer Rapport (on both Firefox 60.0.1 64 bit and Chrome 66.0.3359.181 64-bit).

This problem did not happen before on Windows 10 1709.

Please explain why this problem is occurring and suggest a solution.

Mike Brown

When updating data on financial or commercial websites, Firefox hangs. In the case of Tesco Mobile, when creating a new account and buying a SIM, after about 10 minutes of hanging, the screen changed with this message: "400 Bad Request. nginx/1.11.3". I input exactly the same Tesco Mobile data on Chrome and it updated with only a few seconds delay. I use Windows 10 1803, McAfee Live Safe and Trusteer Rapport (on both Firefox 60.0.1 64 bit and Chrome 66.0.3359.181 64-bit). This problem did not happen before on Windows 10 1709. Please explain why this problem is occurring and suggest a solution. Mike Brown

All Replies (1)

more options

Basically, the 400 error means page not found.

Many site issues can be caused by corrupt cookies or cache.

  • Clear the Cache and
  • Remove Cookies

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

If there is still a problem, Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Did this help?

While you are in safe mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}