Article ID: 124282, created on Jan 25, 2015, last review on Jun 17, 2016

  • Applies to:
  • Plesk 12.5 for Linux
  • Plesk 12.0 for Linux


Uploading .xml license code through Plesk GUI, it gives a '502 bad gateway' and will not install.

Plesk is installed on the server running CloudLinux.

The following error can be found in /var/log/sw-cp-server/sw-engine.log:

[20-Jan-2015 07:07:52] WARNING: [pool plesk] child 916486 exited on signal 9 (SIGKILL) after 10.786705 seconds from start 
[20-Jan-2015 07:07:52] NOTICE: [pool plesk] child 916938 started


This is known issue for CloudLinux, which is caused by ptrace block. Details can be obtained in CloudLinux documentation.

This behavior has been confirmed as a software issue with internal id #PPPM-2446. This issue is fixed in Plesk 12.5.


For Plesk 12.0, as a workaround set kernel.user_ptrace value to 1

# sysctl kernel.user_ptrace=1
kernel.user_ptrace = 1

Then re-upload the license.

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