Shopify login fault since last update
I'm guessing since the last update (or at least since somewhere this week) I suddenly cannot login into my Shopify Admin. In Chrome (cross myself) or the mobile app i have no problems and everything works. Until somewhere last week, there were no problems in Firefox either. No problems seen on any other site. Shopify support can't find any problems on their end. Clearing site cookies and cache no avail. Security settins on "normal". Please see attached screenshot. I can login, but when choosing my store from the store list, i get this error message. Which is a very silly message, since i'm already logged in.
Anyone have any clues?
thanks in advance!