This happens when the resolution setting on your tv box is higher than the resolution of your tv.
It’s an easy fix, you just have to set the tv box’s resolution to a lower setting. Here’s how:
Go to Apps.
Click Apps to open it.
Some boxes will have Droid Settings. If yours does, click it.
Other boxes don’t have Droid Settings, in this case, click on Settings, then scroll down to Advanced Settings.
Click Screen Resolution.
If Auto Switch to Best Resolution is set to ON, switch it to OFF by clicking it and selecting OFF.
Choose the setting beneath the one that is highlighted.
For example, if 1080p-60hz is highlighted, arrow down and click on 1080p-50hz.
Click Escape or the back button to return to the main screen. Done!
Try this new setting.
If you still have the black screen flash, repeat the steps above and choose the next lower setting, 720p-60hz.
Still flashing? Choose 720p-50hz.