I have exactly the same issue here! What's wrong?

The same problem here, also checked with some of my friends, all of them get the "Your request was invalid" - we are from Slovenia (EU). Is this a regional problem?

Just a quick follow up: We just implemented CoreML storage with AWS S3 backend. Works well! But something else also happened today: the Core ML Model Deployment Dashboard appears to be live and kicking! and seems to behave as advertised. A little irony that makes me smile. Thanks Apple!