It appears that the cause is related to Revit 2016 License not registered under Products listed in Account Management
- To verify; Log in to your Autodesk Account Management and check if you have Revit 2016 (or the version you are currently using) is listed under Products
- If it is NOT LISTED; then you need to Address Autodesk Education Community ON THIS LINK and ask them to check your account. This should resolve the issue and get Revit 2016 Educational license added to your Account (Their reply was prompt and they resolved our issue within hours)
- Make the ticket as simple as possible: "Revit 2016 License is not listed under products in my Account Management and this is preventing me (you) from downloading the necessary service packs and from using the related services for this product
- Add screenshot of your account managment page showing the missing Revit 2016 seat
- If you had "Keep me logged in" option checked; you will need to Log out and Log back in again to your account
SIMILAR CASE ON THIS LINK HERE - AutoDESK Forum / Installation & Licensing