Update: (10/05/22 at 14:40)
Turnitin have resolved the issue. They have confirmed that it occurred between 10:22 and 14:05 BST.
Turnitin have reported that they are currently experiencing service degradation. This includes delays in generating or showing similarity reports, and they are also reporting degraded service for Turnitin submissions.
If you are experiencing any issues, please let your module lead know immediately and also log a call with Help4U. As Turnitin currently have the service as degraded rather than down, we suggest that you keep trying to upload your file while they work to resolve the issue.
You can review the Turnitin Status page here, and we will update this blog post when we have any new information.