C ++Output to file is incorrect?

This program is to generate numbers between 0 - 2^32, and I am trying to copy this randomly generated sample into a file, but it gives output as a string of multiple "equal signs(=)'. I don't understand where the error can be from. I also attached an image of the output

#include<iostream>
#include<conio.h>
#include <ctime>
#include<fstream>
#include <cstdlib>
#include <iomanip>
#include <math.h>
#include <vector>
#include <random>
#include <string>

using namespace std;

int main(){

    int ya;
    vector<unsigned long long> instance;
    fstream inFile;
    inFile.open("outputFile.txt");

    if (!inFile) {

        cout << "The file can't be opened" << endl;
    }

    std::mt19937_64 generator;
    generator.seed(std::time(0));
    uniform_int_distribution<unsigned long long>randomNumber(0, 4294967295);

   
    for (int index = 0; index < 10; index++) {
      cout << randomNumber(generator) << endl;
       inFile << randomNumber(generator)<<"\n";
       //instance.push_back(randomNumber(generator));
    }


   
   
    if (inFile.is_open()) {

        cout << inFile.rdbuf();
    }

   
    return 0;
}