When accessing a Turnitin LTI 1.1 assignment through your Learning Management System (LMS), you may encounter the following integration error:
Error message: API Login Failed Oauth_signature incorrect credentials and/or signature calculation
The cause and resolution for this error depends on whether a student or an instructor is experiencing the issue. Select the appropriate tab below:
If a student receives this error when opening a Turnitin LTI assignment, it is usually caused by hidden characters or invalid formatting in the student's LMS profile name fields.
How to resolve:
- An LMS administrator must navigate to the affected student's profile settings in the LMS.
- Completely delete the existing text in the First Name and Last Name fields.
- Manually type the student's name back into the fields.
Note: Do not copy and paste the name back into the fields. Typing it manually prevents hidden spaces, formatting codes, or special characters from corrupting the OAuth signature calculation.
If an instructor encounters this error, it indicates a duplicate LTI configuration in your LMS settings.
This typically occurs when:
- The Turnitin LTI app has been configured multiple times under administrator settings.
- The app is configured at the global account level, but an instructor has also added it at the individual course level.
How to resolve:
An LMS administrator must review the External Apps settings and delete any duplicate or course-level configurations. Turnitin LTI should only be configured once at the global account level.