Hing similar problems today - I can access the 3D Warehouse, but get errors when attempting to download.
Within Sketchup, it just returns Error. On Firefox, it returns the following error - “Looks like there’s a problem with this site
https://download-premium-warehouse.sketchup.com/warehouse/v1.0/content/restricted/7a375ab1-495b-463a-89fe-543c9de0ccb8 sent back an error.
Error code: 404 Not Found
Check to make sure you’ve typed the website address correctly.”