What are signs of reputation collapse?

Reputation collapse manifests through multiple warning signs:

Sudden delivery failures with bounce messages citing reputation issues, blocklists, or policy violations.

Spam folder placement spikes where inbox rates drop dramatically across major providers.

Postmaster Tools deterioration with reputation dropping from High to Medium to Low or Bad within days.

Blocklist appearances on Spamhaus, Barracuda, or other major lists you were previously clean on.

Engagement collapse where open and click rates fall precipitously, often because mail is not reaching inboxes.

ESP warnings or suspensions as your sending platform detects problems.

Collapse is like multiple alarms sounding at once. Any single symptom demands investigation. Multiple simultaneous symptoms indicate crisis mode.