Check IPTV HDMI Connection:

 As the first step, please make sure that the HDMI connection is working fine. Check to ensure that the HDMI cable is correctly connected to both the Nvidia Shield and the television you are using. A dark screen or a screen that flickers might be the consequence of any loose connections.

Distinct HDMI cable or port:

 One must understand that there are different ports on back of the TV. It is recommended that you have to choose the exact HDMI option from screen the port (HDMI port 1 or HDMI port 2). Not only this, if the HDMI still does not connect and the screen is still showing black, you need to try utilizing a different HDMI cable or port on your television in order to determine whether or not the issue has been rectified. 

A change in the display settings: 

Black screen can also appear due to higher video quality that compatible to the TV, it can be resolved by changing the screen display resolution by going to Settings > Display & Sound > Resolution and selecting a different choice from the drop-down menu. If you are using 4K or HDR, you may want to try decreasing it since it might create flickering on certain televisions. 

Look at the TV's settings:

 Motion smoothing and HDMI-CEC are two examples of these types of settings that might cause flickering on certain televisions. Please disable any settings that are not essential that might potentially interfere with the transmission. 

Activate the Nvidia Shield once more: 

In certain cases, the flickering or blank screen difficulties on the Nvidia Shield might be temporarily resolved by just restarting the device. 

Factory Reset: 

In the event that none of the aforementioned solutions are successful, you may want to think about conducting a factory reset. Go to Settings > Storage & Reset > Factory Data Reset to restore the device to its default settings. 

By following these steps, you should be able to resolve screen flickering or black screen issues on your Nvidia Shield. 

If you would want to move further with the IPTV setup or have any inquiries, please don't hesitate to get in touch with us.