SharePoint 2013 Excel Service 401 Error

Posted on June 10, 2021 Updated on September 29, 2021

Recently when I’m working with SharePoint Excel services i received below error message.

“Before Opening Book ObjectSystem.Net.SystemNetworkCredentialSystem.Net.WebException: The request failed with HTTP status 401: Unauthorized. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at ExcelService.OpenWorkbook(String workbookPath, String uiCultureName, String dataCultureName, Status[]& status)”

to get rid of this error you have to disable “Loopback Check” from front end servers and app servers. you can follow these steps to disable Loopback Check.

Method 1: Specify host names (Preferred method if NTLM authentication is desired)

1. Click Start, click Run, type regedit, and then click OK.
2. In Registry Editor, locate and then click the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0
3. Right-click MSV1_0, point to New, and then click Multi-String Value.
4. Type BackConnectionHostNames, and then press ENTER.
5. Right-click BackConnectionHostNames, and then click Modify.
6. In the Value data box, type the host name or the host names for the sites, and then click OK.
7. Quit Registry Editor, and then restart the IISAdmin service.

Method 2: Disable the loopback check (less-recommended method)

1. Click Start, click Run, type regedit, and then click OK.
2. In Registry Editor, locate and then click the following registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
3. Right-click Lsa, point to New, and then click DWORD Value.
4. Type DisableLoopbackCheck, and then press ENTER.
5. Right-click DisableLoopbackCheck, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Quit Registry Editor, and then restart your computer.

Happy Coding