Article ID: 9755, created on Mar 1, 2011, last review on Jun 17, 2016

  • Applies to:
  • Plesk for Linux/Unix


The browser displays 500 Internal server error when trying to access the Plesk Web Interface or websites. Sometimes, only particular pages fail to work; for example, the "License Management" page (Tools & Utilities -> License management).

Note: For a solution to "500 - Internal Server Error", see article #114882:[HUB] 500 - Internal Server Error


Enabling the Linux kernel parameter kernel.yama.ptrace_scope prevents access to the license management page. This parameter is enabled on Ubuntu 10.10 or newer versions by default.


Disable the kernel.yama.ptrace_scope Linux kernel parameter by running the below commands on your server:

# echo "kernel.yama.ptrace_scope = 0" >> /etc/sysctl.conf 
# sysctl -w kernel.yama.ptrace_scope=0

Search Words

particular pages fail to work

503 - Service Not Available

500 Internal server error

503 - Service Not Available

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