How do I connect my sending domain to MailBlue? (DNS)


To send emails via MailBlue, you need to set up your sending domain, which requires authentication. In this article, you will learn how to add your email domain and authenticate the domain by adding the correct DNS records with your hosting provider.

Topics covered in this article

Before you begin

  • You need to authenticate your domain and subdomains before you can send emails.
  • Authentication applies to all MailBlue accounts created on or after 29th July 2020.
  • It may take up to 48 hours for your hosting provider to fully process the DNS records. Keep this in mind, especially if it doesn't seem to work initially. This also applies to domains purchased in the last 24-48 hours.
  • This process also includes the so-called "Custom Mailserver Domains". Mailserver Domains were previously set up manually where necessary, but are now fully included as part of the standard authentication process.
  • Setting up a sending domain includes everything you need for DKIM, SPF, and DMARC. Previously, we used our own Domain Toolbox for this, which is no longer necessary.
  • Domain authentication is required for the following types of campaigns: One-off campaigns, Automated Campaigns, 1:1 Emails, and Notification emails.
    • If the authentication process is not yet complete, a warning will appear when you try to send any of the above emails. This warning includes a prompt to start the domain authentication process.

Linking sending domain to MailBlue

To link your sending domain to MailBlue, you first need to navigate to 'Settings → Advanced → Sending Domain'. Within this environment, you only need to do the following:

  1. Choose which (sub)domain you want to link and enter it. You can do this in the text box labelled 'Enter your domain'. Your sending domain is usually what comes after the @ in your business email address, for example,
  2. Once you have entered your sending domain, click on 'Configure Domain'.
  3. A pop-up will appear with the different DNS records you can use to authenticate your domain.

For now, you are done within the MailBlue environment, and you can proceed with the process at your hosting provider. Any adjustments you still need to make with the relevant party will be indicated in red:

Please note: the value above for 'Mailserver Domain' is just an example, and "xxxxxxx" is not a valid value. You can find the exact value to fill in at 'Settings → Advanced → Sending Domain'.

Authenticate Sending Domain with DNS Records

Authenticating the sending domain is crucial for your email marketing activities. It improves your deliverability, protects against spoofing and phishing, and maintains brand consistency.

As mentioned earlier, this authentication process includes everything you need for SPF, DKIM, and DMARC. These are essential records that need to be set up to ensure your emails are reliably delivered and recipient trust is maintained.

Additionally, the authentication process sets up a "Custom Mailserver." This means you will be using your own server to send emails, instead of a shared server used by all MailBlue customers. This can also have a positive impact on your sending reputation.

General tips for the authentication process

Although setting up DNS records is beyond our scope, we are happy to provide you with some tips that you can apply with most hosting providers. Most hosting providers require the following to set up your DNS records:

  • Type: Choose the relevant type for each row (CNAME or TXT).
  • Name (or Host): Copy and paste the "Name" for each DNS record, such as acdkim1._domainkey (most common) or the full CNAME "Name" like (less common). Which one to use depends on whether your DNS provider automatically adds the domain name to the DNS records you create. If you are unsure which one to use, check the format of other DNS records in your settings (do they include the domain name in the Name or Host field?) or ask your DNS provider.
  • Value (or Content): Copy and paste the "Value" shown within MailBlue for each DNS record (such as
  • TTL (Time To Live): TTL stands for "Time To Live." Use the recommended or default setting from your hosting provider. If there is no default setting, we recommend 300 (5 minutes).

This process, and the terminology it involves, will vary slightly depending on your hosting provider. To find specific instructions for your hosting provider, use your favourite search engine to look up "adding CNAME/TXT record at ..." replacing the dots with the name of your hosting provider. Not sure who your hosting provider is? Then use this handy tool.

In the screenshot below, we show you how to use this tool and where to find your hosting provider:

If you're not sure what to ask your hosting provider, we may have something for you. We have prepared a draft email for you, which you can use to contact your hosting provider: Contact your hosting provider

Checking if authentication is completed

To check the status of your authentication, you can follow these steps:

  1. Return to your MailBlue environment
  2. Navigate back to 'Settings → Advanced → Sending Domain'.
  3. Click here on the desired domain to 'Recheck Verification' to verify if your hosting provider has already implemented the DNS records:

When your DNS records have been successfully implemented, you should see a green indicator under 'Verification status', indicating 'Verified'. Otherwise, there will be a yellow indicator indicating 'Not authenticated':

Please note: As mentioned earlier, it may take up to 48 hours for your hosting provider to fully process the DNS records. Keep this in mind especially if it doesn't seem to work initially. This also applies to domains you have purchased in the last 24-48 hours.

Example (Video explanation)

Although the instructions may vary depending on the hosting provider, which is beyond our scope, we have recorded a short video explaining how to link your domain name to MailBlue and how to properly set up the DNS records with your hosting provider.

In the video, we use TransIP. For settings with your own hosting provider, check the help articles of the respective provider.

For more information on deliverability and sending reputation, you can refer to the following help articles:

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