Super weard, Impossible to log in my Firefox extension, Ids rejected!

On my desktop PC, I can log in Chrome, and in the BW page, also on the Windows app but I cannot in the Firefox app. despite I did it earlier this morning without any trouble.
Very surprising.
I tested very carefully, using the same ID couple, mail and master password, doing a copy paste to be sure, and doing it several times
Did this happen to someone else? I wondering why this can happen. It never did before. I 'm wondering why this can happen. It seems to be related to Firefox, I imagine.

Okay : I closed Firefox, relauched it and could connect then without any problem in the add-on.
Not a big deal, but surprising and worrying in the moment. I was wondering if my account could have been hijacked! the answer seems to be NO, fortunately.