You cannot delete a subdomain from the domain manager if it is currently set as the primary domain for any of your content tools. You will need to first make the domain secondary and then delete.
In your HubSpot account, click the settings iconsettings in the main navigation bar.
Select Website > Domains & URLs in the left sidebar menu.
In the Domains tab, locate the primary domain you'd like to replace and click the Edit dropdown menu and select Replace primary domain.
Click the Select a new primary domain dropdown menu and select your new primary domain. In the example shown here, www.bishathecat.comis currently set as the primary domain for Landing Pages, but it will be replaced with www.vinyasayogabeats.com sowww.bishathecat.com can be deleted.
Click Replace primary domain to confirm your choice. For Marketing Hub Basic or Professional users, the domain you've replaced will be listed as a Redirect domain. For Marketing Hub Enterprise users, the domain you've replaced will be listed as a Secondary domain.
Click Edit, then select Disconnect.
In the dialog box that appears, click Disconnect to remove this domain from your account.