WinRM QuickConfig fails. Error Number: -2144108387 0x8033809D

In a previous post I talked about running a PowerShell script with different credentials on a remote server. This seemed to be working fine, except for one server, so just to be on the save side I tried reconfiguring winrm.

Ordinarily this is accomplished with a simple command:

winrm qc

 However, I was getting an error when trying to do this:

WinRM already is set up to receive requests on this machine.
WSManFault
    Message = WinRM cannot process the request. The following error occured while using Negotiate authentication: An unknown security error occurred.
 Possible causes are:
  -The user name or password specified are invalid.
  -Kerberos is used when no authentication method and no user name are specified.
  -Kerberos accepts domain user names, but not local user names.
  -The Service Principal Name (SPN) for the remote computer name and port does not exist.
  -The client and remote computers are in different domains and there is no trust between the two domains.
 After checking for the above issues, try the following:
  -Check the Event Viewer for events related to authentication.
  -Change the authentication method; add the destination computer to the WinRM TrustedHosts configuration setting or use HTTPS transport.
 Note that computers in the TrustedHosts list might not be authenticated.
   -For more information about WinRM configuration, run the following command: winrm help config.

Error number:  -2144108387 0x8033809D
An unknown security error occurred.

The solution suggested on various places was to set up SPNs for the server, which I did:

setspn -s HTTP/myserver
setspn -s HTTP/myserver.dev.com
setspn -s HTTPS/myserver
setspn -s HTTPS/myserver.dev.com

Alas, this made no difference, after a little bit more digging I realized what the problem was, I was trying to remote to the current server, i.e. from myserver I was trying to run a remote script on myserver [sic], so I added myserver to the TrustedHosts like this:

winrm set winrm/config/client '@{TrustedHosts="myserver"}'