Rule

One-wall · Rule 4.6 Rally

Failure to return

Any of the following constitutes a failure to make a legal return during the rally:

1.) The ball bounces on the floor twice before being hit.

2.) After contact, the ball fails to reach the wall and rebound into the playing zone .

3.) The ball goes off a player’s hand or fist into the gallery.

4.) A ball that obviously did not have the velocity or direction to be returned legally (See Rule 4.4 C) strikes another player on the court.

5.) In doubles, a ball struck by one player hits that player’s partner.

6.) Committing an avoidable hinder ( See Rule 4.9 ).

Mentioned here

Full One-wall rulebook