Document Management, SharePoint integration Permissions

I've just set up SharePoint Integration. 

I successfully set up the integration and  enabled the relevant entities. 

However when I go to test it  admin I get the following message "Collaborate and share files easily with SharePoint–ask your admin to enable it for your team."

I'm sure I'm missing something in permissions but can't work out what to change. 

I'm testing it as Sys Admin, M365 Global Admin and SharePoint site owner. 

Can someone advise me?

Thanks