i got the answer, thanks to smartbear support team.

The ans. is in Testexecute behavior, the Testexecute application check on license availability before getting start, if license is available in the pool then only Testexecute application will open.

Hence in loop i kept running below command, until testexecute open: Start-Process -FilePath $testExecutePath -ArgumentList "/SilentMode /Exit /AccessKey:$AccessKey" -PassThru -Wait