Hi Are you able to access that search engine at?: https://uk.search.yahoo.com/

The desktop Firefox web browser comes with a default list of search engines to use though some locales may have a few changes in search engine options due to location. You can add just about any search engine you want in Firefox including the Yahoo search engine. https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox Would you believe desktop Firefox used to come with Yahoo as one of the default options and was even the default instead of Google for a while. Though it ended pretty suddenly and resulted in a lawsuit and Yahoo being removed from Firefox 57.0 and on. https://support.mozilla.org/en-US/forums/contributors/712925