There are two solution for this.

Solution 1:
Follow SAP note  1948291 - User session (HTTP/SMTP/..) closed aft by increasing the http/security_session_timeout to a higher value (default is 1800). 



Solution 2:
Change the rdisp/plugin_auto_logout as below:

  1. You are getting "error while processing your query" due to User session (HTTP/SMTP/..) closed after timeout

  2. SM21 suggest that funtional module TH_SET_AUTO_LOGOUT terminated the session.
  3. To resolve, change parameter for rdisp/plugin_auto_logout
  4. Go to tcode RZ10
  5. Profile: Browse and select for your instance profile
  6. Edit Profile: Extended maintenance
  7. Click change
  8. Search for this parameter, rdisp/plugin_auto_logout. Highlight and click edit. If not found, go to step 9
  9. Click create
  10. Parameter name: rdisp/plugin_auto_logout
  11. Parameter val. : 6000
  12. Click copy
  13. Click back
  14. Click back
  15. Profile was changed. Save changes: Yes
  16. Click Save (floppy disk icon)
  17. Incorrect parameter values detected. Display value?. No
  18. Do you want to activate the profile. Yes
  19. Click ok
  20. Go to OS level
  21. SAP management console.
  22. Restart the instance.
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