Hi @MERCER, David (DEVON PARTNERSHIP NHS TRUST),
Thank you for posting in this community.
You can take the following approach to troubleshoot your problem:
1.This issue may occur if the SharePoint Web Application ASP.Net Impersonation status has been enabled in IIS. You can disable this ASP.Net Impersonation and check if the problem still persists.
Reference: The request failed with HTTP status 401 Unauthorized.
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2.This error may occur when the Report Viewer control cannot authenticate to the SSRS server. I noticed that your SSRS server and Share Point server are not on the same computer. You can try the following steps:
- Check if you can connect to the SSRS server and the data source directly using SQL Server Management Studio (SSMS).
- Verify that the SSRS server is configured for SharePoint integrated mode and that you have granted database access to the SSRS server in Central Administration. Here is the article about configuring SSRS in SharePoint integrated mode: Install the first Report Server in SharePoint mode.
- Are you using Kerberos authentication? If so, please make sure you have configured the SPNs correctly for the report server and the database server. If not, you can follow this article to Configure SQL Server Reporting Services in SharePoint Server for Kerberos authentication.
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