To go back to an older version you can get that here --> https://ftp.mozilla.org/pub/firefox/releases/ Or you can get a new version from Mozilla. Try downloading and run it from the folder and see if you have the same issue. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

You can 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/100.0.2/system-requirements/

See also https://support.mozilla.org/en-US/kb/install-older-version-firefox

You can check the connection settings.

• Settings -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors
• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can
• https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites