When you try to update your Linux operating system and you get the error.
Because you have not set the proxy server. In this post, I will show that how to set the proxy on your Linux operating system.
Step-1 Create a file in path /etc/apt/apt.conf
Step-2– Add the following lines.
Acquire::http::Proxy “http://user:password@proxyaddress:port/”;
Acquire::http::Proxy “https://user:password@proxyaddress:port/”
Acquire::http::Proxy “ftp://user:password@proxyaddress:port/”