https://www.bleepingcomputer.com/news/security/microsoft-releases-december-2019-office-updates-with-auth-issue-fix/ > Microsoft released the December 2019 non-security Microsoft Office updates that fix issues and add stability and performance improvements to Windows Installer (MSI) editions of Office 2016. > For example, this month's updates fix an authentication issue when connecting Microsoft Project to Project Server online that throws an error saying that "The server you are trying to access is using an authentication protocol not supported by this version of Office."