As the error shows, there is a problem with the software. In this case, I recommend re-installing the Java package. Make sure the IBS Integrator is turned off before doing this. Alternatively, the software can't send the email because there was an error within the application or the port used to send the email is locked because of another application. Close all apps and then try to send he email again. It should work this way. If you still have issues, go to Help > Check for Updates and update the product to the latest version.