There have been a reoccurring problem with Firefox that seems to show up in Linux, Windows, and MacOS. When I log into icloud, I get an error message that the icloud username and password is incorrect, even though the same password has been enter in Safari and other non-firefox browser without issue. I have tried * Run Firefox in safe mode. * Clear icloud site data. * Clear all Firefox browser data. The only fix seems to be to create a new profile, which seems to point to a profile corruption issue. The problem is that the problem return after a while.