To work around this issue, use Outlook Web App (OWA). Therefore, they return a response that causes Outlook to cancel the attempt to add the calendar.įor example, server software that's running on Amazon Web Services (AWS) may consider the authentication broadcast to be invalid and refuse the connection. However, some servers consider the broadcast to be an invalid client request. Most server software responds to this broadcast by supporting modern authentication. Even if the Internet calendar file that you are trying to open does not require authentication, Outlook broadcasts its ability to do modern authentication on the server that contains the calendar. Causeīy default, Outlook 2016, Outlook 2019, and Outlook for Office 365 use a new modern authentication stack. After a progress window opens briefly, you are returned to the calendar module without a new calendar added. Additionally, you don't receive any error message. When you use this method for some Internet servers, the calendar is not added successfully. Provide the path of your Internet calendar file.In the Manage Calendars group on the toolbar, select Open Calendar.You try to add an Internet calendar in Microsoft Outlook 2016, Outlook 2019, or Outlook for Office 365 by following these steps: Applies to: Outlook 2019, Outlook 2016, Outlook for Office 365.You can't add an Internet calendar in Outlook 2019, Outlook 2016, and Outlook for Office 365
