Why can't I submit my app despite setting the content security policy?

I am facing an issue while submitting the app. I have followed the instructions and did the same. I have added the content security policy header in the nginx server, on which the app is hosted. But still unfortunately I am not able to fix this. Can anybody help me out with this issue?.

  1. App must set security headers to protect against clickjacking.
    Your app must set the proper frame-ancestors content security policy directive to avoid clickjacking attacks. The ‘content-security-policy’ header should set frame-ancestors https://[shop].myshopify.com https://admin.shopify.com, where [shop] is the shop domain the app is embedded on.

Thank You.