I try install letsencrypt ssl to my server by this tutorial: https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-14-04 but I got the following errors:
W: Failed to fetch http://ppa.launchpad.net/ondrej/php5-5.6/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ppa.launchpad.net/ondrej/php5-5.6/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found E: Some index files failed to download. They have been ignored, or old ones used instead. apt-get update hit problems but continuing anyway...
WARNING: The following packages cannot be authenticated! libssl-dev openssl E: There are problems and -y was used without --force-yes
Can you help me? How can I install openssl and after that the Letsencrypt? I currently using Ubuntu 14