How to fix error rpc-s-unknown-authn-type in Windows 11

Solution Steps

1. 1 Press Windows key + R, type 'regedit' and press Enter. This opens the Registry Editor. We need to adjust RPC authentication settings.
2. 2 Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc. If the 'Rpc' key doesn't exist, right-click on 'Microsoft', select 'New' → 'Key', and name it 'Rpc'.
3. 3 Inside the Rpc key, look for a DWORD value named 'AuthenticationType'. If it doesn't exist, right-click on the right pane, select 'New' → 'DWORD (32-bit) Value', and name it 'AuthenticationType'.
4. 4 Double-click 'AuthenticationType' and set its value to 1 (which means 'Negotiate' or 'NTLM' depending on context). The exact value depends on your server's requirements. Common values: 0 = None, 1 = NTLM, 2 = Kerberos, 3 = Negotiate. Set it to 3 for most compatibility.
5. 5 Click 'OK' and close the Registry Editor. Restart your computer to apply the changes.
6. 6 If the error occurs in a specific application, check its documentation for the required authentication type and set the registry value accordingly.