Udemy Black Screen Video but Audio working use iPad as 2nd screen

Udemy Black Screen Video but Audio working - Apple Community

having same issue.

sidecar or Duet, both dont work on all browsers i tested. Chrome, Safari, Firefox.

i use my laptop to study with my ipad to play video.

the sidecar (i bought duet before) were great until quite some while recently it no longer work.

i dont see much google complains yet.

tested on macbook air m1, old macbook pro. with various browsers all not working.

external monitor was fine though.

ipad as 2nd monitor doesn't work at all.

appreciate any support.