The COPSTOP JCL does not STOP the COPILOT server
Always get message: server is already stopped

The COPSTOP program delivered with the product establish a connection with the COPILOT server to issue the STOP command.

The connection is established on the COPILOT server port that is to be found in the COPPORT file.
When the JCL is not customized accordingly for any reason, the error is always 'server is already stopped' even though it does not reflect the truth.

You must ensure the JCL DDNAME COPDEFCN is defined as bellow:

//COPDEFCN  DD  DISP=SHR,                              
//          DSN=&QUAL..COPPORT                        

Also, on the MAINFRAME, the best practice is to use the system PAUSE command to shut down COPILOT server.