Error when running but no error on submission

For many of the questions that I submit, I always get either a NZEC, SIGTSTP etc error. But if i submit the solution then it is accepted.
I have wasted so much time because of this problem.
Furthermore, I think there is some serious issue with the editor for submitting code.

So is my solution wrong or is there something wrong with the judge?

Are you clicking “Run” without providing custom input?