https://support.mozilla.org/en-US/kb/update-firefox-latest-version?cache=no Did you update Firefox to the latest version?

Version 86.0, first offered to Release channel users on February 23, 2021

Since you are on Windows XP, you can no longer update beyond the Firefox 52.9.0 version you currently use.

Current Firefox releases require Windows 7 and newer. Users on Windows XP and Vista have been moved to the Firefox 52 ESR version.

• https://support.mozilla.org/en-US/kb/end-support-windows-xp-and-vista