Home Conversations | Reply, organize and find tickets Email Sending Error Filter: The Three States and How to Use as a Work List

Email Sending Error Filter: The Three States and How to Use as a Work List

Last updated on Sep 22, 2026

When to Use

  • You use the sending error filter to find contacts who haven't received a response, and it shows cases that the team has already resolved.
  • You want a reliable work list: only those who are still without a delivered response.
  • You want to understand why a conversation keeps appearing in the filter even after someone has interacted with it.

How It Works

The Three States

The filter has evolved from a simple on/off switch to three options.

Failure in the last send. This is the work list. It shows conversations where a sending failure occurred and no response has been received by the contact since then.

Success in the last send. Conversations that had a failure at some point but where a subsequent response was delivered. Useful for checking what has been resolved.

All. Any conversation with a history of sending failure, whether resolved or not. This is the behavior the filter had before.

What Removes a Conversation from the Failure List

Only one thing: a response that actually reached the contact. This means that two types of messages do not remove the conversation from the list:

  • Private note. It is internal and the contact never receives it.
  • Template, such as a satisfaction survey. It leaves the platform but is not the response the customer is expecting.

This distinction is the main point of the change. Without it, an internal note or a triggered CSAT could hide from the team a contact that still has no response.

The Filter Now Looks Only at Email

The filter now considers only conversations from email inboxes. Previously, when using the "not equal" operator, it also returned conversations from WhatsApp and the widget, which do not have this type of delivery failure.

Notes

  • If your operation used the old filter as a work list, switch to Failure in the last send. It is the equivalent state, excluding already handled cases.
  • A conversation may appear in Success in the last send but still need attention: the state indicates that the last response was delivered, not that the issue was resolved.