Failed to fetch http://packages.linuxmint.com/dists/serena/main/binary-amd64/Packages Connection failed [IP: 208.77.20.11 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/main/binary-amd64/Packages Connection failed [IP: 91.189.91.23 80]
E: Failed to fetch http://archive.canonical.com/ubuntu/dists/xenial/partner/binary-amd64/Packages Connection failed [IP: 91.189.92.191 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/main/binary-amd64/Packages Connection failed [IP: 91.189.88.162 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-amd64/Packages Connection failed [IP: 91.189.88.162 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-backports/main/binary-amd64/Packages Connection failed [IP: 91.189.88.162 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.