I managed to update Ghost to 4.1.2 (after solving some issues with Ghost-CLI). The login still does not seem to work.
Even when I try to use the new portal login I only get “Failed to log in, please try again” when entering mail addresses that definitely belong to members. It’s a problem with custom domains as well as big hosts like Gmail, but it also seems to be quite randomly.
Could there be any settings with the members causing this issue?