Problem with docker multi-arch - cant read yaml file


I’m trying to build a multi-arch docker image based on the example here

I’ve got 2 images - one built on an amd64 linux and another on a raspberry pi 3 which I’ve pushed to my docker hub registry. I’ve written a manifest yml file and am trying to push it using the manifest-tool. But I keep getting this error when I run the command

time=“2018-01-26T10:30:24Z” level=fatal msg=“Can’t read YAML file “multi-platform-manifest.yml”: open /multi-platform-manifest.yml: no such file or directory”

The yml file is in the working directory. I’ve even tried using the fully qualified path name but the result is the same. Any ideas how to resolve this ?