The reviewer is looking for a page whose main purpose is support. A blog post with a comment box further down reads as content, not a support page, so it fails.
What reliably passes:
A dedicated URL (e.g. yoursite.com/support) used only for the app
The app name at the top so the reviewer knows they're in the right place
A visible contact method without scrolling: a support email address or a contact form (social links alone don't count)
Optionally a short FAQ
No login, no "coming soon", and it loads on mobile
I've published 20+ apps and hit this exact rejection more than once. I got tired of rebuilding the same privacy/support/deletion pages for every app, so I built AppLander.io to handle them.
Full disclosure, it's my product. But the checklist above is what actually fixes this, whatever you use.
Topic:
App Store Distribution & Marketing
SubTopic:
App Review