Can I get you to uninstall this please : Default Search Study Add-on 1.0.0 ([email protected]) Mozilla experiment, called 'Shield Studies'. Without even knowing it, you may have volunteered for this Mozilla experiment. Would you go to : Options => Privacy & Security => under 'Data Collection and Use' : Did you uncheck : 'Allow Firefox to install and run studies ' or is it checked ? To check if you are enrolled in these studies : Type in the address bar about:studies Any extensions that you see listed there, you can either disable or remove, just like this Safe Browsing version 4 (at the end of the experiment they will be disabled anyway). See for further information : https://support.mozilla.org/en-US/kb/shield Not thinking thie above is a fix. Have you tried the Extension ? https://addons.mozilla.org/en-US/firefox/addon/app-for-spotify/ Check here for a answer https://community.spotify.com/t5/forums/searchpage/tab/message?advanced=false&allow_punctuation=false&q=Firefox+i Also expand the search as used one word only Firefox This may or may not be a Firefox Issue. You need to explore the site and post here I would think.. Note : Firefox 57 Quantum release date Nov 14th https://www.mozilla.org/en-US/firefox/quantum/ Note : Legacy Extensions will be disabled and or removed. Please let us know if this solved your issue or if need further assistance.