I have a domain that we had been sending emails to in the past without problem. Now when we send an email it gets stuck in the queue with the following error: 

Identity: Smith\59504\296216
Subject: Test
Internet Message ID: <627BF73501BEF54C9EE0B588A0D795770B6C1470@Smith.xxx.com>
From Address: dmd@xxxx.com
Status: Retry
Size (KB): 17
Message Source Name: FromLocal
Source IP: 255.255.255.255
SCL: -1
Date Received: 6/8/2015 2:33:35 PM
Expiration Time: 6/10/2015 2:33:35 PM
Last Error: 440 4.4.0 Local Policy Violation, try again later...
Queue ID: BRADY\59504
Recipients:  kelly@xxx.com

Sending email to that domain from my personal email works.

Any help would be appreciated.

Thanks

It looks like they're blocking your IP address, subnet, domain or something else.  Make sure you're not blacklisted.

You can start here:  http://www.spamhaus.org/lookup/

Hi,

According to your post, I know that cannot send message to one domain with error 440 4.4.0 Local Policy Violation, try again later....
If I misunderstand your concern, please do not hesitate to let me know.

SCL: -1 means that non-spam coming from a safe sender, safe recipient, or safe listed IP address (trusted partner) and will be delivered to recipients inbox.
Basis on the error message Local Policy Violation, it seems that something in those message trigger the spam policies rule.
Do you have deploy third transport agent in your environment? Please run Get-TransportAgent to check.
Meanwhile, do you have enable Forefront Protection for Exchange or default Anti-Spam feature? Please check the IP block/allow list, Sender ID filter and Allow/Block Sender Domains.
I find an similar thread, for your reference: https://social.technet.microsoft.com/Forums/forefront/en-US/9b7656a0-12bc-4b51-8b1a-740086ff1859/totally-obvious-spam-not-being-caught-every-mail-has-scl-1?forum=FSENext