Sign up on Smartarget.online. Configure your Popup app
Sign up on Cloudflare.com and add your domain.
If you registered your domain with another registrar - Point your domain to Cloudflare. If you don't have a domain, you can buy one with Cloudflare.
On Cloudflare - Add a DNS record CNAME : ghs.googlehosted.com (This will point your domain to Google Sites)
On Cloudflare - Go to SSL/TLS section and change it to 'Full'
On Cloudflare - Go to Rules >> Page Rules >> Modify Response Header: Create the following rule:
All incoming requests
Then... Set Static
Header name: Content-Security-Policy
Value: *.smartarget.online
7. Connect the Smartarget app to your Cloudflare domain.
8. On Google Sites - Publish your Google Site, choose a custom domain.
That's it!
Google Sites Popup is powered by Smartarget.online