I have claimed a trial device from headspin. by following the guidelines from https://plugins.jenkins.io/headspin/

I am inserting the right API token and adding artifacts apk app in post build actions. 

I need to run automated test on this device, but build becomes unstable after post build actions. The following error occurs: 

============================= 1 warning in 0.03s ==============================
Exit Code:4

{ "_headspin_progress": ".", "status": 0, "returncode": 0, "stdout": "Success\n", "summary": "ok"}

Build step 'HeadSpin Jenkins Plugin' changed build result to UNSTABLE
Finished: UNSTABLE

My configration is attached in attachment