Error message:
"Authentication Failed Object reference not set to an instance of an object. Please close the window and try again."
The error message means that you've selected a GMail address that does not have a YouTube channel.
Please try the troubleshooting tips below:
1. Choose an appropriate YouTube Channel or,
2. Create a YouTube channel by going to this link: YouTube Studio
- Follow the prompts.
- Enable Live Streaming for the YouTube channel.