gnutls_handshake() failed: Access was denied

Error when running apt-get:

sudo apt-get update && sudo apt-get install yarn

gnutls_handshake() failed: Access was denied

The problem:

There is proxy configuration error of apt-get

The fix:

Define proxy for apt-get

1. sudo vim /etc/apt/apt.conf

2. Add line:

 Acquire::http::proxy "http://web-proxy.il.hpecorp.net:8080";

Source: https://ubuntuforums.org/showthread.php?t=2011511