Adserver.Online uses mail.adsrv.org domain for outgoing emails by default. But if you are a premium plan user, you can set up your own custom email domain via a third-party email delivery service –¬†Mailgun. Alongside other white-label features, using a custom email domain will give your online business a more professional and authentic look. Therefore, we highly recommend this feature to ad networks and agencies that use our service.

How to set your custom email domain up

1. Sign up

First of all, you need to open the link https://signup.mailgun.com/new/signup and create your Mailgun account. 

2. Activate your account

After signing up, you need to check your inbox folder for a "Please verify your Mailgun account" email. Afterwards, you just need to click on the link and you're done!

3. Add a new domain

3.1 Firstly, you need to open this link https://app.mailgun.com/app/sending/domains/new. Alternatively, you can go to Sending/Domains menu and click an Add New Domain button.

3.2 After that, you need to enter your domain name. For example, mg.example.com

4. Verify your domain

Finally, after you complete all the steps listed above, you will need to verify your custom email domain. The verification page opens after you add a new domain, so you just need to follow the instructions. Besides, you can manage your domains from Sending/Domains menu.

After that, your domain should become verified and have a green icon next to it in the domains list.

Custom email domain - Mailgun verified

5. Fill in the data on the Settings / White label / Custom mailer page

In order to set up your custom email domain, you will need the following data:

  1. your verified domain name (for example, mg.example.com)
  2. sender's email (for example, [email protected])
  3. sending API key

To obtain the key, just go to Sending/Domain settings menu

Domain region

When you add a domain, Mailgun allows you to choose from two regions (EU or US).

If you have chosen US as a region, no further actions required.

However, if you have chosen EU as a region you will need to add the "eu:" prefix to your mail domain on our platform.


While this feature is mostly used by ad networks and agencies, every premium plan user can try and see how it works for them.

Please note, this feature is not available to Starter plan users.