Problem connecting to server at http://public.lightning-viz.org

I was checking out the example binder and ran into this error:

Problem connecting to server at http://public.lightning-viz.org
status code: 404

Went to the url and saw it was Heroku, which reminded me of this end of life email I got recently:

https://hello.heroku.com/webmail/36622/960157559/8eb6963c8208f506ee956da036cd7078c6c3c6f30ad6be53ae94995955939d3e