The Firefox UserAgent or UA you used to post this thread appears to be Mozilla/5.0 (Macintosh; Intel '''Mac OS X 10.10; rv:78.0''') Gecko/20100101 Firefox/'''78.0''' It looks like you are using Firefox 78 (likely 78.15.0esr) on the old macOS 10.10 Firefox 79.0 to 115 ESR requires macOS 10.12, 10, 13, 10.14 to run while Firefox 116.0 to current requires macOS 10.15 or later to run. Unless your hardware allows you to update to macOS 10.12 or later to use Firefox 115 ESR, the most current you can run on macOS 10.9, 10.10, 10.11 is the old Firefox 78.15.0esr. 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