Envato Theme check plugin shows warning about add_meta_box

I am working on a wordpress theme and get this warning after theme check in envato theme check plugin. Actually im not getting the exact design issue behind this warning and how to resolve this so please help me to resolve this issue.

WARNING: Found add_meta_box in the file framework/page-options/general.php. Custom meta box functions are allowed for design only. Ensure this is a valid use case.