I upgraded from 2.14 to 2.18 in August, finally. Most of the configuration settings transferred smoothly. Was able to almost trivially re-enable the LTI authentication system, and students and faculty are able to get into WW just fine. Assignment links work fine.
However, grade pass back is just ... not working? I don't see any obvious errors, but nothing is being sent from the WW server back to Blackboard.
Any tips on debugging this process? I don't see anything in the LTI configuration system that hasn't been turned on and configured. I want to have somewhere to start when talking to our Blackboard administrator, to figure out what's going on.
(For context, with 2.14 I've had multiple years of seamless passback, no problems at all. It's the same course database and as far as I'm aware, the same Blackboard configuration)