I have got many issues after running firefox with the command sudo firefox.  Some add ons and many other stuff could not work properly… And I think that you have already known its SYMPTOM , ya maybe it is also the reason why you are reaching this post.

Try the following command:

sudo chown -R yourusername:yourusername ~/.mozilla

If it does not work, you may have to uninstall and reinstalling firefox!

Good luck!