I found the following information section My Groups > How do I create a group? and in My Spaces > Why don't I have the ability to create a Space?
Group/Space creation and access control is limited to Administrators of an organization. Client and Partner members should connect with their Client Success Manager or their Partner Enablement Representative respectively, for approval and access. If you’re unsure of who your organization’s contact is, please send us a request and we will assist.
Since you both are Administrators I would suggest filling out the form in the above link directly to the team involved.