---
title: "Deliverability and Validation of Email Addresses and SMS Numbers"
slug: "email-address-deliverability-and-validation"
updated: 2026-04-21T15:05:08Z
published: 2026-04-21T15:05:08Z
canonical: "knowledge.technolutions.net/email-address-deliverability-and-validation"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://knowledge.technolutions.net/llms.txt
> Use this file to discover all available pages before exploring further.

# Deliverability and Validation of Email Addresses and SMS Numbers

In **Database → Recipient Deliverability**, you can enter an email address or phone number to view messages sent to that address or number, along with a log of message-related activity and suppression list information.

> [!NOTE]
> 💡 *Deliverability* refers to the rate at which messages are successfully delivered to recipients’ inboxes or phone numbers.

## Recipient deliverability

To check on an email address's deliverability:

1. Go to **Database** → **Recipient Deliverability.**
2. From the **Type** list, select either **Email** or **SMS**.
3. Enter an email address or phone number.
  - You can enter an email address that does not yet exist in your database: recipient deliverability lets you view email-related activity and suppression list information for both internal and external emails.
  - Phone numbers default to US/Canada formatting (country code `+1`) unless another code is specified.
4. Select **Validate.**

## Recent activity

**Recent Activity** provides a snapshot of email or SMS activity. Select a message for more detail.

### Emails

Email activity appears for the previous week.

#### Timestamp

A digital record of the time of occurrence of a particular event.

#### Event

When an email is sent, and a recipient takes an action on that message (opens the email), an **event** is captured and made available for display.

There are nine separate email events that can be captured and displayed:

1. Processed
2. Dropped
3. Deferred
4. Bounce
5. Delivered
6. Open
7. Select
8. Spam Report
9. Unsubscribe

#### Detail

For each email that is sent from Slate, a Simple Mail Transfer Protocol (SMTP) response will be returned.

#### Category

Mailings are defined as either transactional or bulk. A transactional email is triggered by an action, like an event registration, while bulk emails tend to be used for campaigns or marketing emails for which there are multiple recipients.

#### Display

Select **Display** to open a popup that includes message information specific to the email event, including links to the original mailing.

- Select **Display Events** to open a popup that lists all of the events that occurred on the email (as enumerated above).
- Select **Resend** to attempt another delivery.

#### Response codes

- **200**: Responses are often successful.
- **400:** Responses are often deferrals. Slate will continue to retry resending `400` messages for up to 72 hours.
- **500:** Responses are hard failures that are not retried.

Recipient deliverability will only return email-related activity for that email address from the last seven days. Additionally, messages sent to an email address as an Admin Notify message (i.e., for a form submission) will not display in this view.

## Suppression lists

A suppression is an email that fails to deliver or has been purposefully prevented from being delivered. An email will be added to a suppression list as a means to protect the sender's reputation.

There are a variety of reasons why an email may be suppressed. For example, if either the email address is incorrect or does not exist, a message may be refused. The email address will then be included on a suppression list.

- **Timestamp**: A digital record of the time of occurrence of a particular event.
- **Type**: Common types of suppressions are blocks, bounces, invalid emails, and spam reports.
- **Status**: Refers to the specific response code returned for each SMTP call.
- **Reason**: A brief explanation as to why the email address was suppressed, as it relates to the response code.
- **Remove:** Select **remove** in order to remove a record from the suppression list. Users will be prompted by Slate to confirm that an email address should be removed from the suppression list.

#### Messages are not resent automatically

To resend a message, first remove the email from the suppression list. Once the email address has been removed from the suppression list, the email can then be recreated and/or resent.

Unlike email-related activity, recipient deliverability will return all suppression list information as it relates to a specific email address, irrespective of the digital timestamp.