How to enable negotiate authentication for winrm

Use Group Policy:

Computer > Policies > Administrative Templates > Windows Components > Windows Remote Management > WinRM Service:
Disallow Negotiate Authentication: Disabled.

Edit the registry key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WSMAN\Client.

Set auth_kerberos and auth_negotiate to 1.

Restart the service.

As suggested in this answer, but Service, not Client:

1. Edit the registry key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WSMAN\Service.

2. Set auth_kerberos and auth_negotiate to 1.

3. Restart the Windows Remote Management (WS-Management) Service.