[Pun] Why can't my player see other players?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Photon.Pun;
using Photon.Realtime;
using UnityEngine.SceneManagement;

[System.Serializable]
public class NetworkPlayerSpawner : MonoBehaviourPunCallbacks
{
    GameObject spawnedPlayerPrefab;

    public override void OnJoinedRoom()
    {
        spawnedPlayerPrefab = PhotonNetwork.Instantiate("Network Player", Vector3.zero, Quaternion.identity);
        base.OnJoinedRoom();
    }

    public override void OnLeftRoom()
    {
        PhotonNetwork.Destroy(spawnedPlayerPrefab);
        base.OnLeftRoom();
    }
}

This is my code for instantiating player prefabs, but the player who joins first can't see any other players.

I have a main menu where once a player joins a room it loads the game scene (if the player is the master client, if not they'll automatically sync scenes with the master) and in the game scene I have a game object with this network player spawner script attached to it.

Why can't the player who creates the room see anyone else?

    void Awake()
    {
        Debug.Log("Current scene: " + SceneManager.GetActiveScene().name);
        spawnedPlayerPrefab = PhotonNetwork.Instantiate("Network Player", Vector3.zero, Quaternion.identity);
        base.OnJoinedRoom();
    }

Welp I tried this and now the results I'm getting are randomly it'll work and randomly it wont work and neither players will see eachother. No clue why sometimes it works and sometimes it doesn't but yeah.

You don't need to call base.OnJoinedRoom(). It is empty.
For instantiation and such, please have a look at the PUN Basics Tutorial. It is a bit dated and all but it really covers these basics and should help.