Why does rand() in C++ keep giving me the same number? [closed]

When I start the program I always get a random number, that works fine. However when I guess the number and then say I want to play again, the number I am going to guess is the same as it was before. I tried putting there srand(time(0)); but that does not work for me. I am only a beginner in C++ so could someone tell me how can I fix it or what to do with it? Here is my code:

#include <iostream>
#include <string>
#include <random>
#include <time.h>

using namespace std;

int main()
{
    srand(time(0));
    int NumberToGuess = rand() % 1000;
    string UserGuess;
    int GuessCount = 0;
        
    bool ContinuePlaying = true;

    while (ContinuePlaying) 
    {
        cout << "Guess a number between 0 and 999" << endl;
        cin >> UserGuess;
        GuessCount++;

        int UserNumber = stoi(UserGuess);

        if (UserNumber == NumberToGuess) 
        {
            cout << "You guessed correctly. Congratulations you won the game." << endl;
            cout << "It took you " << GuessCount << " guesses to guess the number." << endl;
            cout << "Do you want to play again (y/n)?" << endl;

            string playAgain;

            cin >> playAgain;

            if (playAgain == "y") 
            {
                int NumberToGuess = rand() % 1000;
                GuessCount = 0;
            }

            else if (playAgain == "n") 
            {
                cout << "Thank you for playing" << endl;
                ContinuePlaying = false;
            }

            else
            {
                cout << "Error: 505";
                ContinuePlaying = false;
            }
        }

        else if (UserNumber > NumberToGuess) 
        {
            cout << "My number is lower, please try again." << endl;
                
        }

        else if (UserNumber < NumberToGuess) 
        {
            cout << "My number is higher, please try again." << endl;
                
        }
    }
}