Ipad airply replication

I'm trying to replicate my IPad screen (IPad Air2, IOS 15,1) using airplay or recording and following all information I could find on Zoom support pages. 
I got sound on my TV (I guess it's mean that sharing is working) but end with a black screen on my TV, so I don't see the presentation at all.
Some info that could help :  I'm participating and not the organizer of this meeting. 

Any help is welcome !

Guy