Timeout waiting for WinRM if running from non-domain joined agents

[Ray]

We're trying to run packer build for Azure VM images from unattended agents. It happened that everything works if the agents are domain joined. As soon as we switch to non-domain joined machines. The same set of configuration stopped working with following error:

...

2019-08-21T13:50:20Z: ==> Production: Waiting for WinRM to become available...

2019-08-21T14:20:20Z: ==> Production: Timeout waiting for WinRM.

...

The packer version is 1.4.3. Anyone experienced this before? Is there special config needed for non-domain joined machines, e.g. SSL? Thanks!