Can certification guarantee inboxing?

No certification can guarantee inbox placement. MBPs retain ultimate filtering discretion regardless of sender certification status. Certification improves probability but doesn't provide guarantees.

Factors overriding certification: poor engagement with specific recipients, content triggering spam heuristics, real-time reputation problems, recipient complaints, and spam trap hits. Any of these can cause filtering despite certification.

Beware providers claiming guaranteed inboxing through certification. Legitimate programs describe improved probability and conditional benefits. Guarantees indicate misunderstanding or misrepresentation of how filtering actually works.