TestEngine The supplied file is not a valid ReadyAPI project.

I've followed the docs to send a composite project to TestEngine from GitLab. But I'm getting The supplied file is not a valid ReadyAPI project..

The docs say I need to package the repo into a zip. Which I've done in the container. I've verified the zip is correct by unzipping it in the container.

I'm pushing with curl as specified with this command.

But I get: {"code":400,"message":"The supplied file is not a valid ReadyAPI project."} returned. Is there some setting of config piece i'm missing here?