Add Site: I am getting "Unauthorized" with "Error=917656" when I try to add a new SharePoint Online site

Last updated: 2026-10-01

Adding a site in the SharePoint Essentials Toolkit gives and error "Cannot contact web site 'https://tenant-admin.sharepoint.com/' or the web site does not support SharePoint Online
credentials. The response status code is 'Unauthorized'. The response headers are 'X-SharePointHealthScore=7,
X-MSDAVEXT_Error=917656; Access+denied.+Before+opening+files+in+this+location%2c+you+must+first+browse+to+the+web+site+
and+select+the+option+to+login+automatically."

Issue

When you try to add a site you receive an error ''Unauthorized" and "Cannot contact web site"

Details

  • The SharePoint environment requires ‘Modern Authentication’, which means that you need to have the SharePoint Essentials Toolkit registered in Azure Entra ID as an allowed Enterprise App.

Fix / Workarounds

Option 1 - Register the application with Entra ID

See this article to configure the Azure Entra App registration

SharePoint Essentials Toolkit Release - Installation & Deployment

Option 2 - Turn Off ‘Allow Apps that do not use Modern Authentication’

Change the Settings to allow applications that do not support Modern Authentication to access SharePoint:

  1. Navigate to your SharePoint Admin Center

  2. Click Policies->Access Control -> Unmanaged Devices, set to Allow (see below)

    image2020-8-24_12-12-12.png

  3. Click Policies->Access Control -> Access Control -> Apps that don’t use modern authentication, set to Allow (see below)

    image2020-8-24_12-13-51.png

  4. These changes may take up to 30 minutes to take effect.