Quick answer
A few things to check when students are reporting this issue…

Full answer
Firstly, please ensure that they know how to access their feedback. To do this, they need to go to the Turnitin assignment in Moodle and click on the title of their submission.

Also, check that the assignment “post date” has not been set in the future. The assignment “post date” determines the day/time at which students can view their marks and feedback.

Finally, ensure that their browser is not blocking third-party cookies. You can send them instructions on how to solve the issue [link to other FAQ].