IPad Air, Zoom & HDMI

Today I wanted to share my IPad Screen in the lecture room via the HDMI Adapter while simultaneously mirrowing the same screen via "Screen share" in Zoom. Is it true that it is not possible for the IPad Air to do both at the same time? Both worked fine when separatly tried. As soon as I connect to the beamer it is not possible to start the Screencast from Zoom.

Did anyone have the same experience?

Thanks and cheers, Stefanie.