It seems like Certbot is unable to find https://acme-v01.api.letsencrypt.org/. That's... weird.
Is /etc/resolv.conf correct? Does DNS resolution generally work on the system? "dig www.google.com" ?
"curl -v https://acme-v01.api.letsencrypt.org/directory" ?
How about
python -c "import socket; print(socket.getaddrinfo('acme-v01.api.letsencrypt.org', 443))"