vs 2017 not acknowledging my imports?

Question

My visual studio 2017 doesn't seem to want to acknowledge my imports? On building I get error "C2065: 'Registry': undeclared identifier" on line 18, where I make a registry list even though Registry.h is clearly being included. What am I doing wrong here? When I looked for an answer I just found stuff where the error is trying to use something that is not being included.

#pragma once
#include <iostream>
#include <list>
#include "Teacher.h"
#include "Registry.h"
#include "stdafx.h"

using namespace std;

#ifndef LESSON_H
#define LESSON_H

class Lesson
{
private:
    double price;           //Price charged for single lesson
    int maxSize;            //Maximum number of students allowed in the class
    string date;            //Date the class takes place
    int numStudent;         //Number of students currently in the class
    list<Registry> Roster;  //All current registrys for the lesson
    int lessonID;           //Unique identifier
    string name;            //Name of the lesson
    Teacher teacher;        //the Teacher hosting lesson
    string category;        //Named category of the lesson

public:
    Lesson(Teacher teacher, string name, string category, double price, int maxSize, string date);

    ~Lesson();
};

#endif