Hello, Skype has not yet updated their extension to work with Firefox Quantum. Their extension is not developed by Mozilla, so that is up to them. For now you should use the stand-alone Skype Client, it is much faster and more stable than the Web Client anyway. You can get it from here: https://www.skype.com/en/download For more information: https://support.mozilla.org/en-US/kb/firefox-add-technology-modernizing Did this solve your problem or answer your question? If so, please mark as solution.