Linux Mint update manager proxy setting

Behind the proxy server, you can't only modify the setting of Network Manager.

When the update manager doesn't work, please add a file named "95proxies" under "/etc/apt/apt.conf.d/"

And also add following proxy information:

Acquire::http::proxy "http://proxy.company.com:80/";
Acquire::https::proxy "https://proxy.company.com:80/";
Acquire::ftp::proxy "ftp://proxy.company.com:80/";