Not an expert, but was curious and (according to the English version) there no *general* rule allowing you to play the glass wall on your own side of the court as such.
Only in **Rule 14 Correct Return, Point 1.b** it is stated:
>The ball after being hit bounces directly into the opposing court or hits the wall in the players own court first and it
then bounces into the opponent’s court.
➡️ *My interpretation is that only when playing a return, it is allowed to use the glass walls on your own side.*
➡️ *And a return refers to any subsequent stroke/hit after having the ball put in play with a valid serve, but not the serve itself.*
So, bottomline it’s not about “explicitly forbidden”, but rather “not explicitly allowed” during the serve.
From FIP rules 2026 (edit: 2021)
"CASE 1
I hit the ball, and before it bounces for the first time on the ground, it has touched one of the walls of my court or the metal mesh or a light, but it goes over the net and bounces in the receiving box of the opponent's serve. Is the serve good?
Decision: NO, it's a fault."
Makes senses, good points. Ty