1. Insufficient content / Unacceptable site content
Your website doesn’t have enough text on for Google specialists to review.
Google gives a lot of value and attention to the content of the blog before accepting it. If the content is poorly written and has grammatical mistakes Google will reject the blog right away.
Not only the content needs to be grammatically correct, it must be unique and has to provide value to the users and readers of the blog. So the number one reason is the poorly written content on your blog.
2. Page Type / Design of your blog
What will you do if you land a page with full bright yellow background with white text on it, having huge buttons all over the place?
Yes, you’ll never visit that website again .
Blogs which are poorly designed and are hard for the visitors to understand gets rejected by Google AdSense. You must have a good and neat design which comforts the eye and is beautiful in the look.
There are some pages which you must have before applying to Google AdSense if you want to get accepted.
4. Site Does Not Comply With Google AdSense Policies
No rich, unique and meaningful content, no organic traffic, pages with little to no original content or bad user experience through clear navigation and organization.
Your website may be the one that drives traffic through illegal sources, sites with excessive keywords or poorly coded design are usually rejected.
So you need a complete guidance and list of things that you need to do before applying for Google AdSense.