Grading for a student's assignment submission returns 400 Bad Request

26-05-ins-111
Community Novice

Please refer to this submission API - Submissions - Canvas LMS REST API Documentation

We observed "400 Bad Request" response status for some student's assignment submissions. Below is the request payload,

{submission[posted_grade]=[52]}

I would like to know reasons for "400 Bad Request" from above mentioned API. I couldn't find any reasons in the API documentation.

Appreciate your valuable feedbacks.