The Turnitin service has reported that is was offline due to an unexpected outage on Monday April 8th from approximately 1:00AM - 6:20AM PDT. Users of Turnitin and TurnitinUK may have been unable to make/view submissions and experienced delays to Similarity Report generation, as a result of the service outage.
Turnitin reports that all services were functioning normally as of 6:20AM.