You can do anything you like with your Moosend custom domains, including deleting them if they are no longer useful to you!
Here's how to delete a custom domain:
1. Click on the Settings icon in the upper right corner of your Moosend account page.
2. Click on Branding & Domains.
A screen of your existing custom domains appears.
3. Click on the appropriate Custom Domain type tab. The default list will always be that of your Platform custom domains but for this example, let's assume you wish to delete a custom domain for landing pages.
4. Click on the 'three dots' icon to the right of the custom domain you wish to delete, and then click on the delete option.
5. A pop-up message appears at the top of your page, asking you to confirm that you wish to delete the custom domain. Click on the Ok button to complete the deletion.
Keep in mind that you can create a new custom domain whenever you'd like!