Can't play videos with audio on projector in classrooms

Hi Apple Community,



We have noticed that multiple users are experiencing an issue when connecting to our classroom projectors using an HDMI to USB-C adapter and an HDMI cable. When playing a video, it will continually buffer unless we turn off the sound. If the sound is disabled, the video plays without issue.

We have tried the following troubleshooting steps:

• Adjusting screen settings, including mirroring and non-mirroring modes.

• Testing with different browsers.

• Ensuring that the HDMI to USB-C adapter is HDCP-compatible.

• Using a high-quality HDMI cable.

So far, I have only observed this issue occurring with teachers using the MacBook Air M3 running macOS Sequoia 15.1.1.

Searching on Google led me to some discussions about potential DRM-related issues, but I have yet to find a solution. I hope someone here can help provide a fix for this problem.

Thank you in advance!