The debug log provided in [1890026c#5b6f] indicates that there is a new authentication methode for Office365: SAML2.0 SSO.
Maybe related document from M$ which might help understanding the new protocol.
Forums: Unable to login to Skype for Business Office 365
Forums: Unable to login to Skype for Business Office 365
Forums: MFA Error for O365 Account - Brand New Ubuntu 18.04 Install