Whenever you face an error message when trying to add accounts in Live Event Blaster (or when publishing a new item) which more or less looks like "Invalid Credentials, etc" - this is because of missing/broken Client ID / Client Secret / API key.
You can resolve this by creating a new YouTube API Client ID and Secret. Please click on Settings button from Live Event Blaster.
Next visit https://liveblaster.com/api-key to see how you can create a new Client ID and Secret. Once you finished creating these, please paste them in Live Event Blaster: