Black screen then disconnect when Mirroring iMac to LG OLED

I cannot mirror my iMac M1 to my LG OLED65G4 using Airplay. The TV screen goes black after the iMac interface says it is mirroring . After about 30 seconds I get a message that the system could not connect to the LG.

I can mirror with my iPad with no problem.

I had LG look at the TV settings and they are fine. How do I configure the iMac to connect via Airplay?

[Re-Titled by Moderator]