Out serves
Any of the following results in an out:
1.) Missed serve. Any attempt to hit the ball that results in a total miss, or in the ball touching any part of the server’s body other than the hitting hand.
2.) Non-front serve. Any served ball that does not strike the wall first.
3.) Touched serve. Any served ball on the rebound from the wall that touches the server, or touches the server’s partner. This includes a serve that is intentionally caught. When the partner is hit by the serve, the “out serve” penalty supersedes the partner’s foot fault.
Interpretation
Even though the foot fault occurs before the out serve, the out serve penalty takes precedence and shall be enforced. Another example: A server foot faults when contacting the ball and the ball does not hit the wall first. Again, the out serve penalty should be enforced. For this reason, a referee should wait until after the ball is served to call a foot fault.
4.) Two consecutive fault serves. ( See Rule 4.3 C ).
5) Crotch serve. Any serve that hits the crotch of the wall and the floor shall be considered to have hit the floor first.
6.) Out-of-order serve. In doubles, when either partner serves out of order, the points scored by that server since the out of order serving commenced will be subtracted and an out serve will be called. If the second server serves out of order, the out serve will apply to the first server and the second server will resume serving. If the player designated as the first server serves out of order, a side out will be called.