Alexa removed their free offering

[hutcheon]

The CSV file that you are downloading (http://s3.amazonaws.com/alexa-static/top-1m.csv.zip) is no longer updated by Alexa.

They have a new non-free API that can be used (https://aws.amazon.com/alexa-top-sites/). Alternatively, for your purposes, Cisco Umbrella may be used instead (https://s3-us-west-1.amazonaws.com/umbrella-static/index.html), it is a drop-in replacement, but is based on query popularity instead of popularity of the site.

[abshkd]

I met the guys from Cisco Umbrella project or something they used to call it back in Blackhat 2015. They were also publishing DNS reputation data. I never followed up on that. I would definitely look up the project again and see where it's at.