D3 column chart is not working

[numeroteca]

We moved Pageonex.com to a new server following this method (using Docker and an external database) and the D3 chart above the front pages is not working.

See this thread as an example of the current problem: https://pageonex.com/numeroteca/available-space-2/

The problems can be seen in the console log in the browser:

I think the problem is related to http and not https loading, as indicated in the log: Blocked loading mixed content "http://d3js.org/d3.v3.min.js"
This d3 js file is called here /app/views/coding/display.html.erb

One possible solution is to load it from a local version.