GET call doesn't bring down contact property

Hello! I am trying to bring down all of my contacts using an HTTP GET. The problem is the properties I need are not in the returned JSON. I am following https://developers.hubspot.com/docs/methods/contacts/get_contacts and denoted what properties I want with &property. I see some but not others. The properties are not empty for the contact as well. Any ideas as to what is going on here?

SOLVED!

If you go to where the property is listed and click on it, it will show you the “internal name”. This is what you have to use in the GET call.