How can third-party bounce processors mislabel errors?

Third-party bounce processors can misclassify:

Common mislabeling causes:

Outdated dictionaries: Providers changed error formats. Missing patterns: New or uncommon error types. Ambiguous responses: Generic messages classified wrong. Aggressive rules: Treating soft as hard too quickly.

Mislabeling scenarios:

Auto-response classified as bounce. Temporary issue marked as permanent. Block bounce marked as invalid address. Greylisting marked as failure.

Detection:

Compare classification to raw response. Sample audit of categorizations. Monitor for unusual suppression patterns. Review edge cases manually.

Mitigation:

Access raw bounce data when possible. Build verification processes. Provide feedback to processor vendor. Consider supplementary rules.

Trust but verify. Processor convenience does not guarantee accuracy.