Known Issue: Error occurs when creating a Turnitin Assignment in Safari
Turnitin has reported issues arising when students on Apple computers use the Safari browser to access and submit Turnitin assignments in Blackboard, or when instructors create Turnitin asssignments.
When you access Turnitin.com through Blackboard a cookie will be set on your web browser to allow Turnitin to authorise your access during use of the site. You need to ensure that the web browser you are using will allow the cookie to be set by their site, http://turnitin.com
This error occurs for users who set their Safari web browser privacy setting for "Block Cookies and other Web data" to "Always" or "From third parties and advertisers." The issue does not seem to be constrained to any particular version of Safari, and users running versions 10 and 11 in particular have reported difficulties using Turnitin in Safari.
The issue does not seem to be universal with Safari users, however, and Turnitin suggests that turning off cookies in Safari may resolve the issue. We ultimately recommend just using a different browser, such as Mozilla Firefox or Google Chrome, when attempting to create or submit a Turnitin assignment on an Apple computer.
See Turnitin.com for a full list of known issues: https://help.turnitin.com/known-issues.htm