What does it mean when a Collection insert results in a 404?

I have a very simple test app in meteor, and I've created a collection like so:

var people = new Meteor.Collection("people");
 

When I try to do a simple insert, like this:

people.insert({name: "Benson"});
 

I get a 404 error with the text "Method not found". I admit there's a good chance I've fat-fingered something here, but I'd love to know both what's wrong, and why the error is so opaque (i.e. where it's coming from).

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