ERR_NGROK_SHIP_DOCKERFILE_READ_UNAVAILABLE: GitHub failed to return Dockerfile PATH from branch BRANCH (HTTP STATUS) - ngrok documentation

What does ERR_NGROK_SHIP_DOCKERFILE_READ_UNAVAILABLE mean?

ngrok returns ERR_NGROK_SHIP_DOCKERFILE_READ_UNAVAILABLE with this message:

GitHub failed to return Dockerfile <PATH> from branch <BRANCH> (HTTP <STATUS>).

Where can I get more help with ERR_NGROK_SHIP_DOCKERFILE_READ_UNAVAILABLE?

Email support@ngrok.com and include the error code.