There are a few different reasons why you may not be able to create or edit an assignment when logged into home.turnitin.com
1) The class has expired
The class you are trying to add the assignment to may have expired.
Every class created on Turnitin has an end date. When the end date is reached, the class expires and is limited to read-only access. The students and instructor will no longer be able to submit papers or peer reviews, create assignments, or mark any of the papers using online grading.
An expired class can be reactivated by modifying the class end date. Steps to do so, are available on our Reactivating an expired class Help Guide.
2) Your institution's license has expired
If you are unable to access your account or if all classes have become suddenly unavailable to you, your account license may have expired.
In this case, your institution's Turnitin account administrator needs to contact your Turnitin account manager to renew the license.
Once your institution's account is renewed, your classes will become available again.
3) Web-access restriction is enabled
Editing classes or assignments that were created within an integrated Learning Management System (LMS) can cause usage errors on both platforms. Therefore, your Turnitin administrator may have restricted access to the Turnitin website to a view-only state. This means that you cannot complete any actions when accessing via home.turnitin.com and you will need to access exclusively via your LMS.
4) Assignment creation restriction for LMS classes
If the class was created via your institution's LMS, you will not be able to add or edit assignments through the Turnitin website. You will need to manage assignments through your LMS. Please refer to this post on our release notes page for more information.