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

# Authenticating Your Sending Domain

Customize the email address, reply-to address, and sender name your users see when Lumos sends them email. Before Lumos can send from an address on your domain, you need to authenticate the domain by adding three `CNAME` records at your DNS provider. This article walks through copying those records from Lumos and publishing them.

## Prerequisites

* Admin role in Lumos.
* Access to your DNS provider (or the ability to ask your system administrator to add records for you).

## Instructions

### In Lumos

1. Go to Settings → Notifications → Sender Settings to open the "Authenticate Domain" page.

   <Frame>
     <img src="https://mintlify.s3.us-west-1.amazonaws.com/lumos-primary/images/kb/ui-ux/general-lumos-settings/authenticating-your-sending-domain/a5a4916572dd-a84855c7-648f-4a4a-b3b3-115b7fbfa78d2F1777581932233-Navigati.png" alt="Navigation.png" />
   </Frame>
2. Copy the three `CNAME` records shown on the page.

<Frame>
  <img src="https://mintlify.s3.us-west-1.amazonaws.com/lumos-primary/images/kb/ui-ux/general-lumos-settings/authenticating-your-sending-domain/ddda7dd69d73-a84855c7-648f-4a4a-b3b3-115b7fbfa78d2F1777582061707-Authenti.png" alt="Authenticate.png" />
</Frame>

### In your DNS provider

1. Log in to your DNS provider. If you're not sure who hosts your DNS, ask your system administrator.
2. Add each `CNAME` record to your domain's DNS settings. Use the exact record names provided by Lumos.
3. Save your DNS changes.

### Back in Lumos

1. Return to the "Authenticate Domain" page.

   <Frame>
     <img src="https://mintlify.s3.us-west-1.amazonaws.com/lumos-primary/images/kb/ui-ux/general-lumos-settings/authenticating-your-sending-domain/5ac9777ca43f-a84855c7-648f-4a4a-b3b3-115b7fbfa78d2F1777582007291-Notifica.png" alt="Notifications Pending.png" />
   </Frame>
2. Wait for the status badge to change to `Verified`. DNS changes can take up to 72 hours to propagate.

<Frame>
  <img src="https://mintlify.s3.us-west-1.amazonaws.com/lumos-primary/images/kb/ui-ux/general-lumos-settings/authenticating-your-sending-domain/de58689faf4c-a84855c7-648f-4a4a-b3b3-115b7fbfa78d2F1777581979929-Notifica.png" alt="Notifications.png" />
</Frame>

3. Once the badge shows `Verified`, Lumos starts sending email from your customized address.

## Correct CNAME format

The `_domainkey` portion is part of the record name and should be used exactly as Lumos provides it. Do not add a leading underscore.

* Correct: `abc123._domainkey.domain.com`
* Incorrect: `_abc123._domainkey.domain.com`

## FAQ

**How do I check verification status?**

Return to the "Authenticate Domain" page. If the badge shows `Verified`, you're set. Most DNS providers update within a few hours.

**What if the badge never updates to** `Verified`**?**

* Confirm each record name matches exactly what Lumos provided (no extra underscores, no truncated `_domainkey` portion).
* Confirm the records were saved at your DNS provider.
* If it has been more than 72 hours and the records are correct, contact [support@lumos.com](mailto:support@lumos.com).