For more information about when previous versions become ineligible for activation, see You are trying to activate an ineligible previous version You can only activate previous versions that are listed on the eligible previous version list for
Log in as a different user and sign in with your Autodesk Account credentials. Note: After the contract manager assigns the product to you, click If you entered the serial number and product key, but the Activate button is grayed out, contact the contract manager to assign the product to you. You entered the serial number for an individual product rather than the collection serial number If you are activating a product in a collection, make sure you use the serial number and product key for the collection (not the individual product). Error: "Serial number invalid" (Subscription product).Error: "Invalid serial number " (standalone activation).
For more information, see How to find your Host Name and Physical Address. The host ID is incorrect (only valid for network licenses.The machine address, physical address, or host ID is incorrect (only valid for network licenses).The host name is incorrect (only valid for network licenses).
See: Finding Serial Numbers & Product Keys