https://www.bleepingcomputer.com/news/microsoft/microsoft-releases-may-office-updates-with-fixes-for-auth-issues/ > Microsoft released the May 2020 non-security Microsoft Office updates with fixes for several issues and performance improvements to Windows Installer (MSI) editions of Office 2016 and Office 2013. > For instance, the KB4484328 update fixes an issue leading to blank authentication prompts being displayed when offline auth is enabled in Microsoft Office 2016