Reactivate the license:
Be sure that files and folders are not hidden using these instructions.
[*]Remove all files under C:\Users\<username>\AppData\Roaming\Autodesk\ADUT
[*]Remove all files under C:\ProgramData\Autodesk\ADUT
[*]Go to C:\ProgramData\Autodesk\CLM and delete the folder "LGS"
[*]Go to C:\ProgramData\FLEXnet and delete all files that start with adskflex
[*]Go to C:\Users\<username>\AppData\Local\Autodesk\Web Services and delete the file LoginState.xml
[*]Start AutoCAD again.
碉堡了，谢谢