Issue:
When adding the OLC course in the Student records > Achievement > Completed courses
Error 400 - "Value for parameter NonParticipation StatusID is not valid with the provided CompletionStatusId".
Solution:
The error indicates that the Non Participation Status value is not valid with the Completion Status.
Check the Student Record > EQAO accommodations > OSSLT
- Non Participation Status
- Completion Status 
In the case that the Completion status is Not Reported and the participation status is Deferred, you need to change the Completion status for Not applicable - that allow us to change the participation status for None specified.
Once the course is added to the student records, go back to the Student Record > EQAO accommodations > OSSLT and change the Completion status.