Code optimization when searching for ulong prime numbers c#

Question

I am doing the Product of consecutive Fib numbers challenge on codewars (https://www.codewars.com/kata/product-of-consecutive-fib-numbers/train/csharp) and when i have figured out how to do it i am prompted with the message that my code takes too long (over 12000 ms) and I do not know how could I optimize it.

Thank you in advance.

public class ProdFib {
  public static ulong[] productFib(ulong prod) {
        ulong F1 = 0;
        ulong F2 = 1;
        ulong t = 0;


        while (F1 * F2 < prod)
          {
            t = F1 + F2;
            F1 = F2;

            F2 = t;
          }
          ulong[] fib = new ulong[3] { F1, F2, 0};
          for ( ulong i = 2; i < prod; i++)
          {
            if (prod % i == 0)
            {
            fib[2] = 1;
            }
          }
        return fib;
  }

}

Answer 1

for ( ulong i = 2; i < prod; i++)
{
    if (prod % i == 0)
    {
        fib[2] = 1;
        ***break;***
    }
}

By adding break you can speed your code up. But i'm not sure if they pass all the tests

edit:

 public static ulong[] productFib(ulong prod)
    {
        ulong F1 = 0;
        ulong F2 = 1;
        ulong t = 0;


        while (F1 * F2 < prod)
        {
            t = F1 + F2;
            F1 = F2;

            F2 = t;

        }
        ulong[] fib;
        if (F1*F2 == prod)
        {
            fib = new ulong[3] { F1, F2, 1 };
        }else
        {
            fib = new ulong[3] { F1, F2, 0 };
        }

        return fib;
    }

use function like that