First, don't panic — but do act fast. The most common causes are thin content, toxic backlinks, or poor site structure. Run a full content audit and identify pages with low engagement or duplicate value. Consolidate or remove them. Then audit your backlink profile and disavow spammy links. Then rebuild your information architecture around topical clusters rather than scattered keywords. I led a recovery for a major learning platform that lost 65% of traffic overnight — we removed 12,000 low-value pages, cleaned up 8,500 backlinks, and within 14 months traffic had not only recovered but grown an additional 40%.