Content not Being Cached

Customer message

After activating Cloudflare on my site, I am seeing that resources on my pages are not being cached:

< HTTP/1.1 200 OK
< Content-Type: text/html; charset=utf-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0, max-age=0
< Strict-Transport-Security: max-age=10
< Server: cloudflare-nginx
< CF-RAY: 1fa4b922fef517a4-SIN
{ [3507 bytes data]

Why is Cloudflare’s caching not working on my site?