We're trying to integrate an existing LTI tool with Blackboard, and we're unable to have grades properly recognized by the AMI Blackboard instance. When we try with either our own connector, or with a test tool provider (IMS LTI tool provider emulator) any update/read/delete request to the gradebook responds with a NULL response each time. We've had success integrating with other LMS in the past, so we're a bit confused as to what's different on the Blackboard instance.
For tool provider creation, we're using System Admin -> LTI Tool Providers -> Register Provider Domain (with url, key, secret) -> Manage placements. We've also enabled grades and are accessing this through a learner (so we have a valid lis_result_sourcedid and lis_outcome_service_url). We're comfortable using a different method to setup the LTI placement, but we just need to have grades recognized. Additionally, if there's any additional documentation / debugging steps for setting up the gradebook connection, I'd appreciate it.
Please let me know if I need to provide more information.