Error registering new user

It seems like the email server won't let me send out emails. Maybe because i'm on default/local host? Maybe it is my the way my personal email is configured? Either way, there doesn't seem to be any documentation on how to configure the email system or error handling (this caused the server to stop). If it is something I did wrong, I can document it.

```
Node app is running on port 5000
Potentially unhandled rejection [6] {"readyState":4,"responseText":"{\"message\":\"No session\"}","responseJSON":{"message":"No session"},"status":404,"statusText":"error"} (WARNING: non-Error used)
POST USERS: creating a new user. Current count of users: 0
User Registration step 1 succesful
ERROR sending email { Error: Sending failed
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:157:41)
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:228:30)
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:326:28)
at SMTPConnection.g (events.js:286:16)
at emitOne (events.js:96:13)
at SMTPConnection.emit (events.js:188:7)
at SMTPConnection._onError (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:518:10)
at SMTPConnection._actionGreeting (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:893:14)
at SMTPConnection._processResponse (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:669:16)
at SMTPConnection._onData (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:493:10)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:177:18)
at Socket.Readable.push (_stream_readable.js:135:10)
at TCP.onread (net.js:542:20)
errors:
[ { Error: Invalid greeting from server:
554 5.7.1 Service unavailable; Client host [45.37.20.35] blocked using urbl.hostedemail.com; http://www.spamhaus.org/query/bl?ip=45.37.20.35: 554 5.7.1 Service unavailable; Client host [45.37.20.35] blocked using urbl.hostedemail.com; http://www.spamhaus.org/query/bl?ip=45.37.20.35
at SMTPConnection._actionGreeting (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:893:23)
at SMTPConnection._processResponse (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:669:16)
at SMTPConnection._onData (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:493:10)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:177:18)
at Socket.Readable.push (_stream_readable.js:135:10)
at TCP.onread (net.js:542:20)
code: 'EPROTOCOL',
response: '554 5.7.1 Service unavailable; Client host [45.37.20.35] blocked using urbl.hostedemail.com; http://www.spamhaus.org/query/bl?ip=45.37.20.35',
responseCode: 554,
command: 'CONN',
domain: 'juanorozco.com',
exchange: 'mx.hover.com.cust.hostedemail.com',
recipients: [Object] } ] }
/Users/jorozco/projects/donejs/bitballs/services/users.js:192
throw err;
^

Error: Sending failed
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:157:41)
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:228:30)
at DirectMailer. (/Users/jorozco/projects/donejs/bitballs/node_modules/nodemailer-direct-transport/lib/direct-transport.js:326:28)
at SMTPConnection.g (events.js:286:16)
at emitOne (events.js:96:13)
at SMTPConnection.emit (events.js:188:7)
at SMTPConnection._onError (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:518:10)
at SMTPConnection._actionGreeting (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:893:14)
at SMTPConnection._processResponse (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:669:16)
at SMTPConnection._onData (/Users/jorozco/projects/donejs/bitballs/node_modules/smtp-connection/lib/smtp-connection.js:493:10)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:177:18)
at Socket.Readable.push (_stream_readable.js:135:10)
at TCP.onread (net.js:542:20)
```