Error creating CNAB bundle - "Error while dialing: unable to upgrade to h2c, received 404"

Hi I am building CNAB bundle using instructions in this article: https://learn.microsoft.com/en-us/partner-center/marketplace/azure-container-technical-assets-kubernetes?tabs=windows%2Clinux2

Everything works fine until the last step when i issue command:

cpa buildbundle

I get following error:

Failed to build bundle: unable to build CNAB invocation image: error building docker image: listing workers for Build: failed to list workers: Unavailable: connection error: desc = "transport: Error while dialing: unable to upgrade to h2c, received 404"

Any tips what causes that error and how i can get past it.

Thanks,

mmg