What problems are you having with the Skype extension? Just to run through the usual: (1) Does it show on the Add-ons page and can it be enabled? You can open that using either: Ctrl+Shift+a "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then check the list on the right. Disabled extensions cluster at the bottom. Note: It's normal in Firefox 77.0.1 to see a message that the extension is not verified. (2) Does its button need to be added to the toolbar? You can use the Customize tab to check for it if it's not in the expected location. See: [[Customize Firefox controls, buttons and toolbars]] . Are there other issues? I don't use this extension myself.