With the release of Relay 5.1.2, previously authenticated YouTube accounts must be re-authenticated to allow the updated captioning features to function correctly. Re-authentication is required to allow the additional permissions necessary by the updated YouTube API.
Presenters can re-authenticate by simply logging into their Relay Presenter account and clicking on the following button:
NOTE: This is only necessary for Relay Publishing accounts which send video directly to Youtube. Previously authenticated accounts which do not require captioning will continue to publish as normal with no user interaction.