In the past week YouTube has changed the methods it accepts in logging in to a YouTube account (article here).
In short, it now requires that you use the Google Account email and password. If you attempt to log in to your YouTube account through their web interface it will tell you what e-mail account it now requires.
For those sites using the YouTube username you may find that in the coming days YouTube uploads will fail with an Invalid Credentials error. Peregrine will automatically keep retrying to upload the videos, but until the user name and password are changed in the Peregrine Server these errors will continue.
If you are unsure how to change the user name/password or have questions please contact us for assistance.