We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

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

Why mozilla keeps showing a mistake while I try to open facebook?

  • 2 replies
  • 1 has this problem
  • 6 views
  • Last reply by cor-el

more options

This is what appeares when I try to open facebook. It has never happened before and I tried to reinstall Mozilla and install it again and it didn't help. It says something about mistake of a certificate or something. What should I do? Plus, as a bonus, I can't watch any youtube video because it keeps showing a mistake too.

This is what appeares when I try to open facebook. It has never happened before and I tried to reinstall Mozilla and install it again and it didn't help. It says something about mistake of a certificate or something. What should I do? Plus, as a bonus, I can't watch any youtube video because it keeps showing a mistake too.

All Replies (2)

more options

The picture didn't post, sorry

more options

There is security software like Avast and Kaspersky and BitDefender and ESET that intercept secure connections and send their own certificate.

If you can't inspect the certificate via "I Understand the Risks" then try this:

Open the "Add Security Exception" window by pasting this chrome URL in the Firefox location/address bar and check the certificate:

  • chrome://pippki/content/exceptionDialog.xul

In the location field of this window type or paste the URL of the website.

  • retrieve the certificate via the "Get certificate" button
  • click the "View..." button to inspect the certificate in the Certificate Viewer

You can inspect details like the issuer and the certificate chain in the Details tab of the Certificate Viewer. Check who is the issuer of the certificate. If necessary then you can attach a screenshot that shows the certificate viewer.


Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) to see if that has effect.