Can't create subdomain: Error from domain wrapper

[cappac]

When I try to add mail.domain.com following error is thrown:
Error from domain wrapper: mail.domain.com is owned by another user.

I have imported the domain.com account. Other subdomains can be added.
I wasn't able to fix it even though I have tried older solutions posted in this forum.

[ravindradhainwa]

Hi,

You need to remove the entry of mail from DNS Zone.

WHM >> DNS Functions >> Edit DNS Zone

[cappac]

Thanks, this seems to have cured it!