Getting error c2280 at my Update function (at if (Game::vector.at(i).alivez()) specifically) - error-handling

Question

I'm having an error doing the Update when checking if(Game::vector.at(i).alivez()), the error is C2280.
The error says: "Enemy &Enemy::operator =(const Enemy &)': attempting to reference a deleted function. Project: Avoidance Game File:xutility
Game.cpp:
void Game::Init()
{
int i = 0;
while(i< Game::Enemies)
{
srand(time(NULL));
Game::vector.push_back(Enemy(0, (rand()% (int)Console::WindowWidth), (rand() % (int)Console::WindowHeight), rand()%1500/1000.0f));
i++;
}
GameOver = false;
Paused = false;
}
void Game::GameMenu()
{
cout << "1. Start Game\n2. Instructions\n3. Close Game\nChoose an option:";
}
void Game::Instructions()
{
Console::Clear();
cout << "Left arrow = left (duh)\nRight arrow = right (surprise)\nSpace Bar = Shoot\nEsc = Close Game\nP Key = Pause\n ";
system("pause");
}
void Game::fire(Player a)
{
a.mX;
}
void Game::Run()
{
while (!GameOver)
{
if (GetAsyncKeyState(VK_ESCAPE))
{
GameOver = true;
}
else if (GetAsyncKeyState((int)'P'))
{
Paused = !Paused;
}
}
}
void Game::Update()
{
if (!Paused)
{
mPlayer.Update();
for (int i = 0; i < Game::Enemies; i++)
{
Game::vector.at(i).Update();
if (Game::vector.at(i).alivez())
{
Game::vector.erase(Game::vector.begin() + i);
i--;
Game::Enemies--;
}
}
}
}
Game.h:
#pragma once
#include "stdafx.h"
#include "targetver.h"
#include <vector>
class Enemy;
class Game
{
int Enemies = 30;
bool Paused;
bool GameOver;
int Score;
Player mPlayer = Player();
std::vector<Enemy> vector;
public:
void Init();
void GameMenu();
void Instructions();
void fire(Player a);
void Run();
void Update();
};
Enemy.h:
class Enemy
{
enum Enemy_type {NormalEnemy};
Game game;
float mX;
float mY;
float speed;
Enemy_type type;
public:
bool alive;
Enemy(int type, int x, int y, float _speed)
{
switch (type)
{
case 0:
type = Enemy_type::NormalEnemy;
break;
}
mX = (float)x;
mY = (float)y;
speed = _speed;
alive = true;
}
float GetX() { return mX; }
float GetY() { return mY; }
bool alivez() { return alive; }
void Kill() { alive = false; }
void Update();
void Draw();
};