If updating didn't work, resetting the service often fixes corrupted files.
By systematically working through these 20 points, you can resolve the vast majority of AutoCAD license checkout failures. 20 generic license checkout error autocad
Add the following folders to your antivirus/firewall exception list: C:\Program Files\Autodesk\ C:\Program Files (x86)\Common Files\Autodesk Shared\ If updating didn't work, resetting the service often