this problem is probably just annoying a few guys in total, but since I created an Exchange Online Account which is linked to my browser, I can't sign in into my old MTC Account without any signing out of the new MS account from EXO.
I sign out, I want to sign in again and just get logged in into my new account, without even asking for changing the account. Maybe you guys can make instead of the official Microsoft log-in window also an external MTC log-in page.
I just use my EXO env only for training purposes. It's for real annoying.