Authenticating your domains within Dynamics for Marketing is beneficial for a number of reasons. They give your marketing emails credibility, meaning your carefully put together newsletter won’t end up in the junk/spam folder. In order to authenticate your domain you will need to add a few records to your domain. For this example we will be using GoDaddy.
To start the process you need to switch from Marketing to Settings. This can be done using the navigation button shown below.

Select Authenticated domains under Marketing settings

Add a new record and the domain (excluding www.) into the Domain name field. When you hit save the record will reload with newly generated keys. Here you will need to access domains DNS record.

As our domain is hosted on GoDaddy we login to the control panel and select crmcs.london and navigate to Manage DNS

It is here where we copy the values from Dynamics for Marketing into a new DNS record. I copy the Host and TXT value from Dynamics for Marketing record and hit save.

When I have added the TXT I go back to Dynamics for Marketing and click the Confirm DNS registration button at the top of the page. This will check the DNS record has been added in order to authenticate the domain. This can take up to 24 hours so the Ownership status might not change straight away.

If you are experiencing issues with your DNS record not registering then it could be down to the host name provided by Microsoft. Below we added the same record but rather we used @ in place of the host value.

Again this can take time to register but eventually clicking the Confirm DNS registration button should return successful results, which will look like this.

Microsoft have their own in depth post, which covers every base of domain authentication and this can be accessed here: https://docs.microsoft.com/en-us/dynamics365/marketing/mkt-settings-authenticate-domains