UnauthorizedAccessException Error When Listing SharePoint Sites Using App-Only Access

Question

Hello SharePoint Support Team,

I am encountering an issue while attempting to list all sites available on SharePoint using App-based access. Here are the details:

• App Registration: I have registered my app on SharePoint and am using the app-only access method.
• API Endpoint Used: {Tenant_URL}/_api/web/webs
• Access Token: I am passing the access token in the headers as part of the request.

Problem:

When I make the API request, I receive the following error response:

{
    "error": {
        "code": "-2147024891, System.UnauthorizedAccessException",
        "message": {
            "lang": "en-US",
            "value": "Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))"
        }
    }
}

It appears that the app is not authorized to access the required resources, but I am unsure why this is happening. Could you please help me understand what permissions or configurations might be missing or incorrect?

Thank you for your assistance.

Answer 1

Hi @Hardik Purohit,

Thank you for posting in this community.

Are you using this? Granting access using SharePoint App-Only.

If so, the ACS app-only access token is no longer supported in the new SharePoint Online tenant.

But we can change the behavior by running 'set-spotenant -DisableCustomAppAuthentication $false' (needs the latest SharePoint admin PowerShell).

If you're not using SharePoint Online, you'll need to check that your permission XML has been granted enough permissions.

For more information about scopes and permissions in the AppPermissionRequests XML, see the following articles:

Types of add-in permissions and permission scopes

Differences between add-in permission rights and user rights

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