Plesk panel showing error " 502 Bad Gateway, nginx" while accessing.
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Resolution
As a workaround, you may disable aps:
Set apc.enabled = 0 in the /usr/local/psa/admin/conf/php.ini configuration file.
Restart sw-engine:
# /etc/init.d/sw-engine restart
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It will fix the issue.
Reference:
http://kb.parallels.com/en/117480