I have just installed Firefox 67.0.2 64bit on a Windows 10 reinstall on my laptop. Going to use BBC iPlayer I find that I cannot sign in either to BBC home page or on BBC iPlayer page. In either case clicking on the "Sign In" link initiates a page refresh (refresh symbol cycles, although the page does not) and nothing else. This is a new install, so has no history, nevertheless I cleared cache and history; no difference. I then followed the remove corrupt cookie file instruction: no effect. Unless I can sign in I cannot use iPlayer, which is a significant problem for me. Switching to Edge, no problem. Further I have now discovered that the same problem exists on my desktop system (currently Firefox 67.0.1, update on restart, 64bit Windows 10) but the other way round. Here I am signed in to the BBC web site but again clicking the account button simply cycles the refresh symbol. So here I cannot sign out of the BBC. I don't want to clear cache etc here because I would then be signed out and probably unable to sign back in. I have uploaded this problem from my desktop Firefox (the signed in one but with the same issue) and that is the attached Troubleshooting Information Help!