Bad Quality of Video

Hi.
I see my own video cristalclear.
The others see mee in a bad quality.
I work with a Lenovo T530
My Modem is a fritzbox 6430 Cable
The Internet ha 10MB download (I see the others perfect) and 3MB upload.
On wich screw i have to move for a better quality?

is this the official deployment (meet.jit.si) or a custom one?