Most easy solution in Java & it passes all the test cases:

public class Solution {

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int t = in.nextInt();
    for(int a0 = 0; a0 < t; a0++){
        long n = in.nextLong();
        long first = 0, second = 1, sum =0, sumeven =0;

        while(second <= n){
            sum = first+second;
            first = second;
            second = sum; 
            if(sum%2==0 && sum<n){
                sumeven += sum;
            }
        }
        System.out.println(sumeven);
    }
}

}