You will need a FREE Google API key. It takes less than a minute to create one.
Google requires this since April 2015, and all video-related pieces of software will be using this method from now on.
If you ALREADY have a YouTube API key, you will find it here.
If you are creating a YouTube API key for the first time, go to your Google Developers Console and follow the instructions below:
Note: It may take up to 5 minutes for the settings to take effect and your API key to start working.
Article ID: 142
Category: 1-Click Video Ranker