It sounds like an issue with the search string for Google. Ordinarily, this is included in the URL to give Google statistical data about the browser and help Google make any browser-specific changes.

Your best option would be to restore the search engines to their default using the Firefox settings. To do so:

1. Type about:preferences in the Firefox address bar to open the Firefox settings.
2. Select Search from the sidebar.
3. Scroll to the One-Click Search Engines section.
4. Click the Restore Default Search Engines button.
5. You may need to choose the default search engine again from the Default Search Engine section above.

Hope this helps.

Sounds like a broken search engine where the & is missing to add an extra parameter (&client=firefox-b).

You can inspect the builtin default search engine by pasting this chrome URI in the location/address bar

• chrome://browser/locale/searchplugins/

Try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.

• https://www.mozilla.org/en-US/firefox/all/