I’m testing my company’s LTI integration in Blackboard. Upon posting a grade from our external tool back to Blackboard, I receive the error ‘signature_invalid’, pointing to an issue in the OAuth signature. I’ve verified our signature process, and it’s currently working in multiple other LMS’s. I’ve also verified date/time syncing on the Blackboard development VM, so I don’t believe this is a timing issue. Any input on the issue is much appreciated. Thanks!