The UserAgent or UA you used to post this thread. Mozilla/5.0 (Macintosh; Intel Mac OS X '''10.11'''; rv:78.0) Gecko/20100101 Firefox/'''78.0''' It appears you are using Firefox 78.0 (possibly the 78.15.0esr) on the old eol macOS 10.11 Firefox 78.15.0esr was the latest to support the macOS 10.9, 10.10, 10.11. Firefox 79.0 to 115.0esr requires macOS 10.12, 10.13, 10.14 to run. Firefox 116.0 to current requires macOS 10.15 or later to run. If your hardware allows for a macOS update to 10.12, 10.13, 10.14 then you can run the Firefox 115.0 ESR which is is currently still supported with updates till 115.27.0esr in August unless Mozilla extends updates again. https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support