Working out what happened.
FIRST, CONFIRM IT
Compare like with like: the same period length, accounting for seasonality. Traffic falling in a quiet month may be normal.
Check whether it is all traffic or only organic.
THE POSSIBLE CAUSES
A technical problem: the site was down, pages returned errors, or something blocked crawling
A change you made: a redesign, a migration, changed URLs, a noindex left in place
A search engine algorithm update Increased competition Seasonality A manual action or security issue Tracking broken, so the traffic is there and not recorded
DIAGNOSING
Check Search Console for manual actions and security issues first Check the indexing report for pages dropping out Check whether specific pages or the whole site declined Check whether specific queries declined Correlate the date with anything you changed
THE MOST COMMON CAUSES
A migration done without redirects A noindex directive left from staging Robots.txt blocking the site
Check those three before anything else.
