Scenario / Questions

When I try to install any plugin on my Jenkins server, I get below error in the browser. I can see the list of Available plugins. Error occurs when I select any plugin and click on Install without restart or Download now and install after restart.

Error in Chrome:

This page isn’t working
xxxxxxx didn’t send any data.
ERR_EMPTY_RESPONSE

xxxxxxx represents server name.

Error in Firefox:

The connection was reset

The connection to the server was reset while the page was loading.

    The site could be temporarily unavailable or too busy. Try again in a few moments.
    If you are unable to load any pages, check your computer’s network connection.
    If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

URL shown the browser address bar:

http://xxxxxxx:8080/pluginManager/install

What am I missing here?

My environment:

Server OS: RHEL7
Jenkins version: Jenkins ver. 2.121.1
JDK version: OpenJDK Runtime Environment (build 1.8.0_171-b10)
OpenJDK 64-Bit Server VM (build 25.171-b10, mixed mode)