Dear whoever,
I recently got a Selmer Paris Metal Jazz mouthpiece.
It is a C**,
I`ve been trying to play it with a Vandoren size 3 but for some reason I have been unable to play notes from the high G and down.
So I switched to a 2 1/2 but it is still doing that. Any advice would be fine. Please help...

Please keep in mind, I have been playing for 5 years but I am not very smart when it comes to different kinds of mouthpieces and it is also my very first time ever using a metal mouthpiece.