Deliverability / Bounce Investigation
Start from recent evidence before changing sender or audience strategy.
Evidence tier describes my hands-on relationship with the content. Official sources describe platform contracts/documentation. Production observations should not automatically be treated as official limits.
Scope the incident
Which send/job, domains, audience segment, time window and sender identity are affected?
Pull recent bounce diagnostics
Use _Bounce or Tracking Extract to capture category/type/SMTP reason/code.
Separate recipient vs ISP patterns
Group by domain and bounce category; look for concentration and temporary blocks.
Check subscriber state
Inspect held/bounced status and historical bounce count where relevant.
Review recent changes
Audience source, send volume, sender profile, authentication, creative/link changes and acquisition quality.
Choose remediation from evidence
Do not remove or suppress broadly before determining whether the issue is permanent, transient or configuration-driven.