Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

does not solve problem

Contact their support and ask about this.

I had this problem also. You are probably outside the U.S.A or using a different language on your browser correct? You need to change or add English to your browser languages. Then it should work again.

Let me know if it works for you.