Are you using Firefox in Private Browsing mode?

If you are, you need to give add-ons the ability to run in Private Browsing mode. See Extensions in Private Browsing for more information.

Hope this helps.

I am not using private browsing.

Do you see messages in the Browser Console about these extensions if you check this console after starting Firefox ?

• "3-bar" menu button or Tools -> Web Developer
• https://developer.mozilla.org/en-US/Tools/Browser_Console

tried to detect trackers before rules were loaded 4 background.js:287 Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. webrequest.js:107 tried to detect trackers before rules were loaded 9 background.js:287 Promise rejected after context unloaded: Actor 'Conduits' destroyed before query 'RuntimeMessage' was resolved 3 messaging.js:1 tried to detect trackers before rules were loaded 19 background.js:287 DataCloneError: The object could not be cloned. ExtensionChild.jsm:813 tried to detect trackers before rules were loaded 5 background.js:287 DataCloneError: The object could not be cloned. ExtensionChild.jsm:813 tried to detect trackers before rules were loaded 45 background.js:287 Key key_application of menuitem Application could not be found menu.js:292 tried to detect trackers before rules were loaded 26 background.js:287 OpenGL compositor Initialized Succesfully. Version: 2.1 INTEL-14.7.8 Vendor: Intel Inc. Renderer: Intel(R) Iris(TM) Graphics 540 FBO Texture Target: TEXTURE_2D tried to detect trackers before rules were loaded background.js:287

I have loads of messages there