A 'System Error' occurred when using Vijos & jd4

I configured vijos (including jd4) on my own server, after submitting a program, it showed system error, prompting me BrokenPipeError(32, 'Broken pipe').

My code: (as you see, it's A+B problem)

//cpp
#include<cstdio>

using namespace std;

int a,b;

int main()
{
	scanf("%d%d",&a,&b);
	printf("%d\n",a+b);
	return 0;
}

I couldn't find out what's wrong with jd4, so I come for help.

By the way, my online judge is: http://118.25.95.87:8888/

[twd2]

Can you please provide the logs of vj4 and jd4?

[undefined-moe]

You can try HydroJudge instead of jd4.

[twd2]

You can try HydroJudge instead of jd4.

???