Decide if the following sentence is grammatically CORRECT or INCORRECT.

Volleyball spielt man nicht in dem Stadion.

correct

incorrect

incorrect

Translation: Volleyball is not playing in the stadium.

can you explain why?

google translate is sometimes not accurate ;)

Since its not the correct way, you might instead say "Volleyball is not played in this stadium"; you can't say "playing" since volleyball can't act on its own and the whole sentence must stay in the past tense.

Volleyball spielt man nicht in dem Stadion.

Sounds good to me, and implies that
"One does not play volleyball in the stadium"

If you want to say:
One does not play volleyball in a stadium or
Volleyball is not played in a stadium
then

Volleyball spielt man nicht in einem Stadion.

Correct you can say so in german.

The explanation reiny gives is perfect!