yes it is a service fault
Volleyball does not have fouls although there is a lift and a foot fault which could be considered fouls.
A foot fault is when in volleyball you serve and you pass the line or put your foot under the net.
While serving, if the player's foot breaks the line, it is considered a foot fault, and the opposing team is awarded a point.
No, that would be a foot-fault.
When the person who is serving steps over or on the service line.
Doubles, net violations, out of rotation, foot fault, lift, etc.
It is called a foot fault. You can also have a foot fault if you step over the center line onto the opponent's court.
It is called a "foot fault".
A foot-fault is when the player serving steps over the back boundary line while in the process of serving. You must stay within all out of bound's lines when serving.
What has "professional" got to do with it ? A foot fault is a foot fault.