Field notes
Cloudflare fix guides
Cloudflare rarely tells you a rule did not run. It tells you the request succeeded. A Page Rule can be enabled, correct and permanently shadowed; a purge can return success having cleared nothing; a redirect loop can appear with no deploy at all. Each note takes one of those, explains why it is silent, and gives you a script that asks the API instead of guessing.
Every problem here comes from a component behaving exactly as designed. First-match-wins rule evaluation is a legitimate model. An idempotent purge API is correct. Flexible SSL exists for origins that genuinely cannot do TLS. Nothing is broken in isolation — the failure lives in the combination, which is why neither end reports it and why you have to look at the whole configuration rather than the piece that looks wrong.
Cloudflare
ERR_TOO_MANY_REDIRECTS is almost always Flexible SSL
Cloudflare connects to the origin over HTTP, the origin redirects to HTTPS, Cloudflare follows it back. One setting causes the loop.
A Cloudflare rule that never applies because the record is grey-clouded
Cache rules, redirects and WAF only run on proxied records. A grey-clouded hostname bypasses Cloudflare entirely, so the rule is never consulted.
Only one Page Rule applies, and it is the one at the top
Page Rules do not stack. The highest-priority match wins and every other matching rule is skipped, silently.
A cache purge that reports success and clears nothing
Single-file purge misses objects cached under a custom cache key or with certain request headers. The API returns success either way.
These are the ones I keep hitting. If yours is broken in a way none of them describes, tell me on LinkedIn — it is usually how the next note gets written.