While creating and updating record for Submission resource, getting an error "user not authorised to perform that action"

[ManojBhosale]

When tried to create a new record (submit an assignment) and update (grade or comment on submission) the existing record through POSTMAN, getting an error "user not authorised to perform that action". From our end, we have already ensured that the other resource id like assignment_id and course_id that we are providing in the request URL are present in the same account and under the same domain. Also confirmed that the requesting user is enrolled in that course and section under the same domain. Can anyone help to provide the work around or suggestions for this problem? For more reference, you can check the attached screenshots of the request and error response in the postman.