HTML parsing failure?

This was my first time using oga, and I tried parsing the page https://www.freshsales.io/api/

I am unable to find the divs I am after. I can find them using nokogiri.

Granted the page doesn't validate properly: https://validator.w3.org/nu/?doc=https%3A%2F%2Fwww.freshsales.io%2Fapi%2F

require 'uri'
require 'net/http'

def get(url)
  uri = URI(url)
  body = Net::HTTP.get(uri)
  body.encode('UTF-8', invalid: :replace, undef: :replace, replace: '')
end

page = get('https://www.freshsales.io/api/')

oga = false

if oga
	require 'oga'
	doc = Oga.parse_html(page)
	path='//div[@class="api-url"]'
	doc.xpath(path).each do |node|
		puts node.text
	end
else
	require 'nokogiri'
	doc = Nokogiri::HTML(page)
	path='//div[@class="api-url"]'
	doc.xpath(path).each do |node|
		puts node.text
	end

end

Any idea where the problem lies?

It would be great if there was a section on how to troubleshoot oga.