Final Challenge: What's wrong with my code here?

Strange one this. Your code works if you use puts instead of print:

contact_list = [
  {"name" => "Jason", "phone_number" => "123"},
  {"name" => "Nick", "phone_number" => "456"}
]
contact_list.each do |i|
  i.each do |j , k|
    puts "#{k}"
  end
end

Why? I don't know, but I'd like to find out. I'll have a little google.

In the meantime, I think this code is a bit better like this:

contact_list = [
  {"name" => "Jason", "phone_number" => "123"},
  {"name" => "Nick", "phone_number" => "456"}
]
contact_list.each do |hash|
  hash.each{ |key, value| puts "#{value}" }
end

Ok, actually I wasn't looking closely enough at my terminal when I was experimenting. Your code actually performs as expected. It returns:

Jason123Nick456 => [{"name" => "Jason", "phone_number" => "123"}, {"name" => "Nick", "phone_number" => "456"}]

See, it prints out the values as expected and then returns the whole array. I'm not sure why it returns the whole array, but it's probably not all that important for this exercise, and puts also returns the whole array, except that puts adds a new line after each value. You can google for further reading. Using puts returns:

Jason
123
Nick
456
=> [{"name" => "Jason", "phone_number" => "123"}, {"name" => "Nick", "phone_number" => "456"}]  

I expect that would probably pass the test.

EDIT: You actually need to use |contact| instead of |hash| in the challenge. But anyway, it ACTUALLY turns out that this doesn't pass the test, even though it returns the exact same result as what they want to be returned. They probably need to amend this.

To pass the test, you have to specifically declare "name" and "phone_number" even though, in this example, it's not necessary to get the required output:

contact_list.each do |contact|
  puts contact["name"]
  puts contact["phone_number"]
end

It is more readable and understandable though, to be fair, which is important.