Proxychains: I can't figure out how to make it work

Question

Here is my config file. The proxy I use for testing comes from here.

I don't want to use Tor. I just want a normal proxy.

When I run for example proxychains firefox-esr ipleak.net:

• if I use exactly the config file from above, I get the error:

error: invalid item in proxylist section: https 185.198.189.21 8080

• if I change https to http, I have no error in my terminal, the browser starts, but the page won't load and gives me an error after some time:

What am I doing wrong?