Please follow the steps below and change the mentioned file.
1. Shut down the application.
2. Navigate into <Servicedeskplus-MSP> /conf directory.
3. Open the file web.xml in an editor.
4. Search for the following line :
<session-config>
<session-timeout>360</session-timeout>
</session-config>
Change 360 into 20 or 30 or according to your requirement. This value is in minutes.
5. Save the file and close.
6. Start the application.
Now any technician who is idle for more than mentioned time, then he will be logged out automatically.