First thing is to try to remove your YouTube account and then try to add it again.
This usually fixes the problem.
If the problem is not fixed, and you receive error messages like "YouTube quota exceeded", try to go to
Make sure that Client ID/Secret fields are blank (empty).
If they are not empty, then remove any data and hit SAVE API.
Once you save the settings (clearing the client id/secret) go back to YouTube accounts section of Lingo Blaster.
REMOVE all accounts and then re-authorize them (re-add them)