Ghost+Aws lightsail distribution does not work

i used aws lightsail instance as ghost host, and want to use lightsail distribution as CDN,

the distribution setup as follow:

but,distribution url only is

Welcome to nginx!

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.

Commercial support is available at nginx.com.

Thank you for using nginx.

anyone could help me?