Sharepoint CSOM .NETCore: Many queries coming back as Access Denied

Hosek, Andrew 6 Reputation points
2021-04-28T21:53:58.337+00:00

Suddenly today many tasks that we use daily are erroring out with the message:

Access denied. You do not have permission to perform this action or access this resource.

This is using CSOM on .NETCore 3.1.

Some examples of the tasks that aren't working are changing the title of a site, getting alerts from a user on a site, creating a subsite, and I'm guessing there are more.

I tried the same exact tasks with the same user using CSOM on .Net Framework 4.7 with no issues, so it seems like its only an issue with .NETCore. I have only tried on 3.1 though.

Microsoft 365 and Office SharePoint For business Windows
Microsoft 365 and Office SharePoint Server Development
Developer technologies C#
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  1. Duane Arnold 3,216 Reputation points
    2021-04-29T01:08:27.907+00:00

    If you're getting an 'access denied' it has something to do with the permissions the user account has when using a program that is being denied access to resources.

    On the most recent Windows O/S(s), a user admin account is only a standard user with UAC enabled. You have to allow UAC to escalate user account privilege's to Admin.

    Or where the resource is located, like on another machine, the user account being presented by the program to access the resource doesn't have the permissions.

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  2. MichaelHan-MSFT 18,126 Reputation points
    2021-04-29T06:16:19.23+00:00

    Hello @Hosek, Andrew ,

    I did a test on my end, SharePoint CSOM works fine on my end with .Net Core.

    How do you authenticate to SharePoint in .NET Core? You need to use modern authentication with CSOM for .NET Standard. More details are here: https://learn.microsoft.com/en-us/sharepoint/dev/sp-add-ins/using-csom-for-dotnet-standard

    If you are using app for authentication, could it be that the app expires?


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