The Turnitin service, which EMU uses through Moodle, will be unavailable because of scheduled maintenance on March 17, 2018 between the hours of 11 AM and 6 PM. Turnitin is a third-party service–EMU has no control over when they perform scheduled maintenance.
Their notification about this maintenance window states:
Users will be unable to submit and grade during this maintenance window, so please ensure that any submission deadlines are adjusted to fall outside of the window.
Turnitin provides a system status page which may contain updates about this outage.