What does this judgement mean?

I am solving NSUDOKU. On submitting my solution I get this verdict…

:( internal error occurred in the system

What does this mean? Why isn’t my solution accepted even though it satisfies the conditions given in the question?

If you get an internal error this is not due to anything you have done - it is an error on the Codechef server. You may need to just try again later; alternatively, sometimes it will display an internal error but you will still be able to see the result of your submission by clicking on the My Submissions link on the problem page.

It has given ‘wrong answer’… What’s wrong in my solution? It does solve for what is asked in the question

Its not wrong. Internal error has no special symbol and shows WA as symnol. Nothing wrong. Also there might be an error in the judge.

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