Outlook 2016 fails to load with "The operation failed"

Hi. This problem is driving me mad.

I have a clean install of W10Pro. The W10 user is set-up on O365 Azure AD. Our mail goes through O365.

I installed Office 2016 ProPlus (clean install). Initially I've put all'user info/email into Outlook to set-up account, but Outlook the failed to load. Now it fails to load all the time. Almost immediately it trows"The operation failed" (a small window with no error code, no explanation, nothing - just OK).

I've tried everything - uninstall-reinstall, /safe, /resetnavpane, changing DPI (it is 100% on clean install), deleting profile and deleting Outlook profile files. Nothing changes. The latter gives me couple of additional seconds of Outlook attempting to load, but then trows the same error. With all other methods and normal loading attempts the error is almost immediate.

Any ideas would help.