---
title: "\"Bounced\" vs \"Invalid\""
description: "Difference Between “Bounced” and “Invalid” Email Address"
url: https://help.crono.one/en/articles/41-bounced-vs-invalid
collection: "Tasks"
updated: 2026-10-08
language: en
---

# "Bounced" vs "Invalid"

Difference Between “Bounced” and “Invalid” Email Address

### Intro

Crono shows four email states: **Valid**, **Accept-all**, **Unknown** and **Invalid**.

This article explains the difference between an email that **Bounced** and an address marked **Invalid**, and why an address can turn red without anyone having emailed it.

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### **1\. “Bounced” Definition**

**Bounced** means a send was attempted and the receiving server rejected it: the system receives a delivery failure message from the email provider, indicating that the email was **returned** (not delivered).

-   In this case, the email address is automatically **marked as “Invalid”** - red dot - to prevent future failed sends.
    

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### **2\. “Invalid” Definition**

**Invalid** means Crono knows the address will not deliver, so it is not used for sending. A bounce always leads to Invalid, but a bounce is not the only route in - an address can be labeled as **Invalid** in several ways:

1.  **Caught by Bounce Shield:** an address Crono found through enrichment is re-verified and comes back undeliverable, before any send is attempted. See section 3.
    
2.  **Triggered by a bounce event:** if an email bounces, it is **automatically marked Invalid**.
    
3.  **Manually set by a user:** a user can manually mark an address as Invalid.
    
4.  **Verified during manual input or CSV import:** when manually added or imported, an address may be checked and flagged as Invalid.
    

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### **3\. Bounce Shield**

**Bounce Shield** is Crono's check on email addresses it found through enrichment. Shortly after an address is found, Crono re-verifies it in the background with an external validation service. Addresses that come back undeliverable are marked **bounced**; the rest of the batch is confirmed as valid.

When that happens, every active contact in the workspace holding that address flips to email **Invalid** - the red dot - and the address is not used for sending.

This is why an address can turn red shortly after it was found, without anyone having emailed it. A red dot is **not** proof that a send bounced.

Bounce Shield runs on its own. It costs no credits, requires no action from you, and there is no setting, button or progress indicator for it - the only thing you see is the address changing state.

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### **4\. Possible Causes for Multiple Invalid Addresses**

If many addresses are marked Invalid during a campaign or sequence, potential causes include:

-   **Actually invalid email addresses** that naturally bounced.
    
-   **Bounce Shield** flagged them after enrichment, before any send was attempted.
    
-   **Provider-specific issues (e.g., Outlook)** incorrectly returning messages as spam.
    

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### **5\. Recommended Actions**

-   Review bounce logs to determine if errors are temporary or permanent.
    
-   Report unusual patterns (e.g., valid domains like Outlook returning messages).
    
-   Avoid re-sending to addresses already marked as Invalid.