How to upload a document from a subsite in Sharepoint to Outlook

[MarijkeCe]

Hello, 

I'm trying to upload a document from a subsite in Sharepoint to Outlook. When navigating to "add from a cloudlocation" --> "Groups" only the document library of the main sharepoint site is visible, not the subsite. 

Thanks for your help.

[#2]

I@BryanLewis42 I'm europe based, please assist by mail.