Guideline 4.2.2 - Design - Minimum Functionality

Apple finds that your application is too similar to your site or is not app friendly enought.

Use a mobile optimized theme (like WPMobile.App or some examples on codecanyon)
Think your app for a mobile user. If a page isn't ideal for the app, create a new page just for the app.
Be sure to remove any unnecessary page and block on the page. Be as light as possible.

Remove all links pointing to your website
Use a social network page instead of your website as support url
Put your privacy policy in a pdf and host this file on a different website (or use https://wpmobile.app/privacy.pdf)
Be sure that all the screenshot display the last version of your app theme (use this tool to get new screenshot)
See this guide for more informations about the publication process