To get the letsencrypt to work with SuddenLink who blocks port 80 and 25 use this:

    sudo certbot certonly --manual --preferred-challenges dns -d bartonphillips.org,www.bartonphillips.org

Certbot gives you a secret TXT key to add to the DNS record for bartonphillips.org on DigitalOcean.com.
The key that certbot gives you  must be reset each time. Certbot will give you a new key and you
need to add it to the DNS TXT record each time you renew.

Make a CNAME: _acme-challenge (_acme-challenge.bartonphillips.org)
under bartonphillips.org.
Then it all works.