Error Message: Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.

Error Message: Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.


Action:
When I run an SSIS package under the SQL Job Agent, I get the following error message. 

Error Message:
"Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application."

Solution:
The license key verification failed. To find out the specific issue, modify the job step execution command line to include the "/REP V" option and run your package again. Now the execution log will include verbose information.