Hi @Ana ,
Whether you created a new private office 365 group in SharePoint online mobile app?
Per my test, we couldn't create it in SharePoint mobile app, if possible, please provide more information.
Steps to delete a SharePoint team site with Office 365 groups:
- SharePoint in Microsoft 365 team site — Settings > Site Information> Delete site — Check box to delete group, and then click Delete.
Or try to delete a private group in Microsoft 365 admin center with proper permission, such as Groups admin role:
- Go to the Microsoft 365 admin center >Active Groups under Groups menu> Select the group you want to delete->Delete Group
If it is not feasible for you, please feel free to reply.
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