If the class end date has passed, the Class ID will no longer work, and you will not be able to join.

Turnitin classes are designed with automated start and end dates chosen by the creator. If a semester has officially concluded, or if the instructor accidentally selected an early expiration date, the Class ID will lock out new enrollments.

Sometimes the problem is not the Class ID, but the device. Browser extensions (like ad-blockers), outdated browser versions, or corrupted cache/cookies can interfere with the enrollment script on the Turnitin webpage. If the credentials are correct but the system hangs on a loading screen or throws a "processing error," the student should try clearing their browser cache, disabling extensions, switching to a different browser (Chrome, Firefox, or Edge), or using a different device entirely. Turnitin works best on updated browsers.

This comprehensive guide explains how to find, use, and troubleshoot Turnitin Class IDs, whether you are managing a course or submitting your first assignment. What is a Turnitin Class ID?