When I attempt to upgrade the plugins from the GUI:
"Manage Jenkins" -> "Manage Plugins" -> "Updates Tab" -> "Check the box next to any plugin" -> "Click Install"
I get that following error msg.
java.io.IOException: Server returned HTTP response code: 500 for URL: http://updates.jenkins-ci.org/download/plugins/jobConfigHistory/1.11/jobConfigHistory.hpi

When I log into the server and run the following CLI wget command it works and downloads the plug in.
"wget -d --proxy-user=svc_abeadm --proxy-password=XXXXX http://updates.jenkins-ci.org/download/plugins/pmd/3.17/pmd.hpi"

In "Manage Jenkins" -> "Manage Plugins" -> "Advanced Tab"
I have the proxy settings set to the same settings I have set for the proxy on the linux server.

This is really causing a lot of pain and headache and we are now less and less inclined to upgrade to the latest version of Jenkins because that means we have to manually update 30+ plugins.

I appreciate your time and helps,

Kenan