Content controls have to be top-level controls in a content page or a nested master page that references a master page.

In master page I am using asp content place holder. And in my child page I am using pure html coding. When I attach master page in my child page I am getting this error.

Content controls have to be top-level controls in a content page or a nested master page that references a master page.

How to Solve this, share your ideas....