You may check to see if you have a valid Keysight ADS license for Sonnet and your ability to both check a license out and check the license back in. To check for license availability, select Sonnet ⇒ Help ⇒ Support ⇒ Check License from the main menu of the layout window in ADS. The Status Dialog window appears and provides status on the license. Pictured below is a successful license check.
When you are running a simulation using the Analysis Simulate command, the Keysight ADS Interface is locked until the analysis is complete. You may not make any changes or execute any commands in the interface until it is unlocked when Sonnet is closed.
If for some reason the Sonnet program is interrupted in such a way as to prevent a graceful shutdown, such as a hung program or a program crash, then the Keysight ADS interface is not unlocked. In this case, you may manually unlock it by selecting Sonnet ⇒ Analysis ⇒ Unlock Project from the main menu of the ADS layout window.