Can anyone help me out with this. I've had no problem doing this for years, however yesterday I installed a fresh copy of windows 10 pro (MS download tool), and installed a fresh latest copy of Office Pro Plus 2019 VL (O365 deployment tool). When I open outlook and enter ANY office 365 email account, or outlook.com account, it brings back the standard windows credential prompt, rather than the single sign on / modern authentication / 2FA / MFA style prompt. Anyone know why this has suddenly started happening, and how to fix this? I have tried both the latest version (I think LTSB2018 10357.20081) and the oldest version (LTSB2018 10336.20015) I have tried manually creating the profile and selecting O365 / outlook.com Thanks!