can't play any content when connected to external display.

This is due to DRM. The issue is not with Apple, Apple is doing what it should do i.e. block screen recording. The issue with DisplayLink who are attempting to screen record a DRM source in order to display it elsewhere. The workaround is to unplug all external monitors or quit out of DisplayLink.

Thanks; I was trying to figure out why it displayed black on the inbuilt display and a directly connected display and forgot that "DisplayLink" utilizes Screen Recording API. I expected the DisplayLink displays to not show HDCP video, but didn't realize use of that API blocks playback of HDCP on native HDCP compatible displays.

This may be a DRM issue.

Hollywood is big into shoving HDCP DRM into everything, so you can't make copies of video, unless they allow it (e.g., temporarily, on your cable company's DVR). If this MacWorld article is correct, it appears that programs other than iTunes can't verify that your monitor is crippled with HDCP. When they can't, they intentionally refuse to play 'protected' video, and you get the black screen.

https://www.macworld.com/article/228703/oops-you-cant-play-most-protected-digital-video-on-an-external-mac-monitor.html

If the article is correct, Apple could provide a way for programs other than iTunes to do this check. Or Hollywood and the streaming providers could remove the DRM … like the record companies eventually did with AACs and MP3s sold through the iTunes Store and Amazon MP3 Store. But I wouldn't hold your breath waiting for the latter to happen.

Disable graphics acceleration in web browser e.g.

In Google Chrome:

Disable 'Use graphics acceleration when available' in System Settings > System.

I had the same problem and accidentally was able to solve it.

Here are the items I have:

• MacBook Pro 14"
• 2 HDMI Connector
• 1 VGA Connector
• 2 Monitors
• 1 HMDI converter to USB-C

Connect both monitors to each other with the one VGA connector. Connect each monitor's HDMI to MacBook. Since the MacBook only has 1 HDMI outlet, I used the 2nd HDMI converter to USB-C to connect to the MacBook. Then I was able to view all streaming services (Prime Video, Netflix, YouTube, etc.) on both monitors.

Hope that helps!

sourav95kr Said:

"can't play any content when connected to external display.: When I am connected to external display all the media sites like Apple TV and Netflix and prime video show only black screen with audio. I am using multiple monitor setup using DisplayLink hub."

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Mirror the Screen:

While opened on the Mac, try mirroring the Mac, or extending it. Use either of these screen shortcuts:

• [command + F1]
• [command + dim-brighness]

Having this issue for a while now.. thanks for this quick fix!