Error message 401.2.: Unauthorized: Logon failed due to server configuration. When application deployed

Question

I have an asp.net 4.0 application that works fine running under cassini but when i deploy to IIS i get the above error. It is running under the Default App pool which a numb

Answer 1

I resolved 401.1 and 401.2 authentication errors by adding BackConnectionHostNames to the registry using these directions: https://support.microsoft.com/en-us/help/896861/you-receive-error-401-1-when-you-browse-a-web-site-that-uses-integrate (Method 1)

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

These errors were occurring on a Windows 10 Professional install running version 1803, on a domain that is named differently than the site I was attempting to authenticate to.