Docker content trust – docker push signed image not working for ARM device

I am trying to use docker content trust on an ARM device to push/pull signed images to a Docker Hub public repo. I set the DOCKER_CONTENT_TRUST environment variable, then docker login to the repo and attempt to docker push a signed image.

Whether I try to docker push a signed image to a Docker Hub public repo or an Azure private container repository I get the same error: “you are not authorized to perform this operation: server returned 401.” This occurs when the docker push gets to the “Signing and pushing trust metadata” step.

I verify the docker login was successful and check that the repo credentials are stored in the $HOME/.docker/config.json file.

Docker version 18.06.0-ce, build 0ffa825
Debian GNU/Linux 8.7 (jessie) on ARMv7 device

Steps:
export DOCKER_CONTENT_TRUST=1
docker login -u <username -p <password
docker push <image

Has anyone had success using Docker content trust on ARM devices?

Thanks