Postfix connection timeout sending email

So I've been testing out my new linode. Very happy!

I decided to dive into setting up email for the first time, I followed this guide: https://library.linode.com/email/postfi … 0.19-mysql">https://library.linode.com/email/postfix/postfix2.9.6-dovecot2.0.19-mysql

I followed it to the dot, except for changing the personal details.

It works find when receiving emails. But when I try and send an email to an outside domain, the client hangs on "connected to smtp.example.com" and eventually times out without sending.

mail.log output looks like so

May 27 22:15:09 linode postfix/smtpd[9027]: connect from client.exampledomain[xxx.xxx.xxx.xxx]
May 27 22:16:51 linode postfix/smtpd[9027]: lost connection after UNKNOWN from client.exampledomain[xxx.xxx.xxx.xxx]
May 27 22:16:51 linode postfix/smtpd[9027]: disconnect from client.exampledomain[xxx.xxx.xxx.xxx]

Anyone have an idea whats wrong here?

Thanks