So what does the error screenshot say? And where are you doing the upgrade from what site?

This can possibly happen if your Ubuntu Linux distribution has reached end-of-life and is no longer supported with updates. You can switch to Firefox from the Mozilla server, but verify that you meet the System Requirements (GTK+ and GLib) for the current Firefox release. *https://www.mozilla.org/en-US/firefox/system-requirements/ *https://www.mozilla.org/en-US/firefox/110.0/system-requirements/ You can find the full installer of the current Firefox release (110.0) in all languages and all operating systems here: *https://www.mozilla.org/en-US/firefox/all/#product-desktop-release *https://www.mozilla.org/en-US/firefox/110.0/releasenotes/