The committee have had (non specific) protests regarding players not serving correctly. The following points should be observed to serve correctly.
A legal service must adhere to the following rules :
1.The ball rests freely on the open palm of the hand.
2.The hand holding the ball must be above the level of the table.
3.The ball should be projected upwards (at least 16 cm)
4.The ball should be struck when it is falling and behind the table.
More information can be found on line at ITTF