Step 1: Confirm the drop is real
Before chasing fixes, verify the data. Pull conversion rate by traffic source for the last 30 days vs the prior 30. If only one source dropped (paid search but not organic, for example), the issue is upstream — not your page. If every source dropped equally on the same day, you have a tracking problem or a site-wide regression. Cross-check with a secondary system: server logs, Stripe sign-up counts, your CRM. If one system disagrees, your tracking is the issue, not your conversions.
Step 2: Did anything change on your side?
Pull your deploy log. The single highest-probability cause of a conversion drop is a code change you shipped. Common culprits: a form library update broke validation on certain browsers, a CSS change pushed the CTA below the fold on mobile, a third-party script (chat widget, analytics, A/B tool) is throwing JS errors that block the form. Open your page in DevTools, check the console for errors, complete the form on three devices. 70% of "conversion drops" we see in audits are caught here.
Step 3: Did anything change on the visitor side?
If your code is clean, look at traffic. Run a paid campaign that ended? Brand search dropped? Reddit thread that was sending you traffic got deleted? When the high-intent traffic dries up, conversion rate drops even though nothing on your page changed. The fix isn't on the page — it's restoring the source. Run an analysis only if steps 1 and 2 don't surface a cause; otherwise you'll optimize a page that wasn't broken.