Symptoms

Server uses proxy for internet connection. During the running Plesk installer proxy was configured, but 502 Bad Gateway error appears during downloading the files.

Cause

Proxy server configuration issue.

Resolution

Please contact your local network administrator to:

1. Make sure to clear/disable proxy server's cache.
2. Make sure proxy has proper configuration that allows to download files from

NOTE : Use the following link for your reference: Changing the Updates/Upgrades Source .