If the client and the remote machine aren't on the same domain, you have one of two options:
- use HTTPS as a transport protocol
- add the remote machine to the list of trusted hosts on the client
In order to configure WinRM to use HTTPS, open up a PowerShell console as administrator on both machines and run:
winrm quickconfig -transport:https
and open port 5986 on the firewall:
netsh firewall add portopening TCP 5986 "WinRM over HTTPS"
Alternatively, you can add the remote machine as trusted host on the client by running:
winrm set winrm/config/client @{TrustedHosts="10.0.5.35"}