Failed to fetch https://download.docker.com/linux/ubuntu/dists/trusty/stable/binary-amd64/Packages  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

W: Failed to fetch https://download.docker.com/linux/ubuntu/dists/trusty/edge/binary-amd64/Packages  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

E: Some index files failed to download. They have been ignored, or old ones used instead

sudo apt-get remove docker docker-engine docker-ce docker.io