No valid licence found.The program will quit

I bought Cubase 12, entered the code in web, also in steuberg app.
It worked okay, but sometimes if i quit and start cubase again the following notice comes:
No valid licence found.The program will quit.

What shoul i do

When this occurs, try killing the Steinberg License Engine process using the Task Manager.

Please also make sure that the Steinberg Activation Manager is updated to the latest version. It’s currently 1.4.10.

It sounds like something (possibly a third party plug-in) is causing Cubase to silently crash on quit. Can you check if Cubase is generating crash/freeze dumps? On Windows, they’re stored in the %UserProfile%\Documents\Steinberg\CrashDumps\ folder.