Error TVAPP-00236

This is a bug that appears to be the result of xfinity. There is a discussion on xfinity's support page: https://forums.xfinity.com/t5/XFINITY-Stream-Website/Streaming-error-TVAPP-00236-unsupported-display/td-p/3344318

However, they are claiming that it's a bad adapter, cable etc. Xfinity is trying to lay blame at the end user. However, it simply is put that if you use a second monitor with your iMac with Safari (and I tried Chrome too) you get this following error:

It was sometime (if I can remember correctly) before March where I was able to have a second monitor connected just as I do right now. When I got this screen shot, the channel worked for about 5 seconds, then the error popped. So it looks like Xfinity checks to see if there is a second monitor connected and then if it's present it will block.

I can play the video just fine if the second monitor is unplugged. So its not a browser issue. Only when a second monitor is detected.

Also by the way one of their technicians tried to claim that it was because Xfinity stopped supporting flash. They said Safari couldn't handle HTML5/TS Streaming. As a mac os dev I find that quite humorous. I do say that i'm a developer very loosely, just started to learn... But I know that Apple was the first onboard with TS video. They just are coming up with excuses.

Good afternoon Neugierig2012,

Welcome to the Apple Support Communities!

It sounds like you are not able to AirPlay to your Toshiba LCD TV. Are you trying to do this from your MacBook Pro or from an iPhone or iPad?

What macOS is running on your MacBook Pro? Do you have an Apple TV device?

The resources below will help you address this issue:

AirPlay system requirements

Use AirPlay to stream video or mirror your device’s screen

Take care.

Just a slight update.

Here is my setup. I have a iMac late 2012 macOS Catalina ver 10.18.7

I have a display to HDMI cable coming from mac to TV.

Also tested (because of the first post) I tried a TV with AirPlay capability and same result.

So hardwired using adapter or Airplay the error occurs.

Just for laughs, I started a video, it started playing with no monitor/airplay. Afterwards, I connected the second monitor and it worked. The video is playing. SO, it's Xfinity that checks for second display and blocks the use on video startup. After I connected it the check must have been done, and it's playing fine. But if I start the video when the second display is connected, it says that it cannot support the display.