You verify info@company.com. SMTP returns 250 OK. You send your campaign. Amazon SES reports a hard bounce — "Address not found."
Nothing was wrong with your copy. The address was catch-all: the domain accepts every local part during SMTP verification, but the specific mailbox does not exist.
This is one of the most expensive mistakes in B2B outreach — and it is entirely preventable.
What Catch-All Really Means
A catch-all mail server accepts RCPT TO for any address on the domain:
>>> RCPT TO:<fakeperson123@company.com>
<<< 250 2.1.5 OK
Verification tools correctly label this catch_all — not valid. The mailbox was never confirmed; only the domain's accept-all policy was detected.
Google Workspace, many European SMB hosts, and legacy IT setups use catch-all intentionally. For marketers, the label means: "We cannot prove this inbox exists."
Real-World Damage
When catch-all addresses slip into outreach:
| Impact | Typical symptom |
|---|---|
| Hard bounces | 5–15% on catch-all-heavy lists |
| SES suppression | Repeated bounces throttle your account |
| Reputation hit | Gmail/Outlook lower trust in your domain |
| Wasted credits | Sends that never reach a human |
We learned this firsthand running agency campaigns: addresses marked catch_all in Company Finder bounced after send when the old rules allowed them through. Valid-only preflight fixed it.
Valid vs Catch-All vs Risky
| Status | SMTP signal | Safe for cold email? |
|---|---|---|
| valid | 250 OK + mailbox confirmed | ✅ Yes |
| catch_all | 250 OK but domain accepts all | ❌ No — use caution |
| risky | Inconclusive / greylisted | ⚠️ Re-verify later |
| invalid | 550 / no mailbox | ❌ Remove |
Your verification tool should never treat catch-all as deliverable for outreach. On Email Validator, mass mail and campaign preflight block everything except valid.
What to Do With Catch-All Contacts
Don't delete them blindly — they may still be useful:
- Find alternate contacts on the company website (contact form, LinkedIn)
- Try Email Finder patterns (
hello@,firstname.lastname@) and verify each - Segment separately — some teams A/B test catch-all with tiny volume (we don't recommend this for SES cold outreach)
- Keep for research — company is real even if inbox isn't confirmed
How to Enforce Valid-Only Outreach
Whether you use our mass mail tools or your own ESP:
- Verify the full list before sending
- Filter to
validonly — not catch_all, not risky - Run a preflight report showing sendable vs blocked counts
- Suppress bounces immediately (SES webhooks → suppression list)
Company Finder lists now mark non-valid contacts as blocked for mass mail selection automatically.
Bottom Line
Catch-all is a verification result, not a green light. Treat it as "unknown deliverability" and keep it out of cold outreach unless you have independent proof the inbox exists.
Verify before you send — Try Single Check free →
Related: Catch-All Email Explained · Email Verification Statuses Explained