Knowledgebase

This article helps when users cannot add a team to a group or cannot add a standalone team.

On the Office 365 Groups page, you can create groups of user accounts that you can use to assign the same permissions to in SharePoint Online and CRM Online. For example, an administrator can create a security group to grant a certain group of people access to a SharePoint site. Only global and user management administrators have permissions to create, edit, or delete security groups.

Read the full article at https://support.office.com/en-us/article/create-edit-or-delete-a-security-group-in-the-office-365-admin-center-55c96b32-e086-4c9e-948b-a018b44510cb