Failed to validate the SSL certificate errors are often just temporary connectivity issues, resolving themselves when you try again later (as @jasperfrumau suggested). However, I don't recall seeing those types of errors with
ERROR! Unexpected Exception.
If it doesn't resolve by trying later, or adjusting your identity on the network (use VPN, visit coffee shop, etc.), could you give us more context? Echoing @jasperfrumau, it'd be nice to see the complete verbose debug output (add
# verbose provision
ansible-playbook server.yml -e env=<environment> -vvvv
# verbose deploy
ansible-playbook deploy.yml -e "site=<domain> env=<environment>" -vvvv