Sharepoint / Teams not showing custom DL on a mobile device

Hi, I created a Document Library in a site. Next I opened the it in Teams and added the new DL as a new tab. All this works on my laptop. But when I open Teams on a tablet or smartphone I get an error when trying to open the tab. The error is: "This item might have been deleted, expired, or you might not have permission to view it. Contact the owner of this item for more information." I open Teams with the exact same user??? Any ideas?