Do bounces always mean the address is bad?

Myth: Bounces always mean bad addresses.

Reality: Bounce cause varies:

Address-related bounces:

User not found: Yes, address is bad. Domain invalid: Yes, address is bad. Mailbox disabled: Address bad at this time.

Sender-related bounces:

Blocked for reputation: Address is fine; you are the problem. Content rejected: Address is fine; message is the problem. Authentication failure: Address is fine; your config is the problem.

Technical bounces:

DNS failure: May be temporary. Connection timeout: Infrastructure issue. TLS problem: Configuration, not address.

Why it matters:

Suppressing address does not fix sender problems. Block bounces require different remediation. Diagnosis determines response.

Not all bounces are equal. Read the bounce to understand the real problem.