Google said 53 pages weren't indexed. All 53 returned 200. Here's what was actually wrong.
Google Search Console told me 53 pages on one of my sites were "not indexed." I assumed the sitemap was broken. So I tested every single URL.
All 53 returned HTTP 200.
That's when I stopped trusting the warning label and started reading the actual data.
What was actually wrong
1. Eleven articles were missing from the sitemap entirely. Not broken, not 404, just absent. One of them was the landing page for a keyword cluster pulling 30 impressions a month — I'd been optimizing a page Google had never been told existed.
2. A CSS bug that the warnings never mentioned. While checking the homepage I found raw CSS rendering as visible text at the top of the page. Cause: a </style> tag had been closed early during a redesign, so roughly 460 characters of stylesheets — including the rule that centered the hero image — sat outside the tag. The image wasn't centered because the centering rule was being displayed as body text instead of applied.
Two different bugs, one root cause: nobody opened the page after the redesign. My 60-point pre-deploy check passed all of them, because it validates content and structured data, not whether the page actually renders correctly.
The process that found it
Nothing clever — just refusing to accept the summary:
- Pull the full URL list from GSC (not the 10-row default — you have to change rows-per-page to 500 to see everything)
- Test every URL: status code, noindex headers, and whether the final URL matches the requested one (catches redirects)
- Diff tested pages against what's actually in the sitemap
- Open the homepage and look at it
435 URLs tested. 0 real 404s. 11 missing sitemap entries. 1 CSS leak.
What I'd tell anyone running a content site
Search Console warnings describe symptoms, not causes. "Not indexed" doesn't mean "broken" — it can mean "never submitted," "redirecting," or "crawled and judged not worth it." Those three need completely different fixes, and the summary view won't tell you which one you have.
The other lesson is more uncomfortable: automated checks gave me false confidence. Everything was green while the hero image was uncentered and CSS was leaking onto the page.
I do this kind of diagnosis for other people's sites too — if you want a second pair of eyes on yours, details are here: /