Sorry the wrong link: https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/temporary-residents/study-permits/post-graduation-work-permit-program/permit.html#authorization
Summer break? Weird that they rejected you for a summer break. Did you explain it in a LoE in your initial application? Or any document from your school specifying that was a summer break?