Seems like https://artifacts.elastic.co/ is down and all attempts to download software are failing.
Can you confirm? I'll try again in a bit (I could be doing something wrong 
)
Getting: ERROR 503: Service Unavailable: Back-end server is at capacity.
from
https://download.elasticsearch.org/elasticsearch/marvel/marvel-latest.zip
I am also getting ERROR 503. I don't think you are doing anything wrong.
Sorry, everyone. The downloads are hosted on S3, which, if you've seen Twitter and such, is having issues right now.