sharepoint online – Designation of a new O365 group site problem

I want to create an O365 group with the same name as a classic Sharepoint site which has now been deleted.

The old site was called http: // site name / marketing
This site has been deleted.

I then create an Office 365 group but the resulting site is called http: // sitename / marketing1. It should be marketing!

Why is this and how can I get this URL (I don't mind deleting this O365 group and recreating it if necessary).

Thank you