A rejection reason is a configurable field when rejecting a candidate or prospect from a job and is categorized into three main types:
- We rejected them
- They Rejected us
- None specified
By default, rejection reasons are required whenever a candidate and/or prospect is rejected in your organization.
If your organization chooses not to enforce a required rejection reason it can deactivate the requirement by clicking the Configure icon 
in the upper right-hand corner and navigating to Permission Policies on the left-hand panel.
Navigate to the All Users header on the subsequent page and uncheck the box to the left of When rejecting a candidate, make "Rejection Reason" a required field.
Note: If your organization has deactivated the rejection reason requirement and would like to enforce the requirement again, follow the above steps to add a check in the appropriate checkbox.