SBS Server MSExchange smtp queues have frozen messages and also received NDR shown in body of question from another domain.
Posted on 2010-09-02
The following recipient(s) could not be reached:
email@example.com on 9/2/2010 2:36 PM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<myserver.local #5.5.0 smtp;554 Denied (Mode: normal)>
This all began after some network (dsl modem, firewall) changes and supression of a spambot attack (cutwail) that had my client blacklisted for a few days. After configuring FW rules to prevent SMTP outbound from any but the SBS server I delisted and most email is flowing freely.
The stuck messages are still retrying from what I can see in firewall activity on port 25 and I did enable verbose logging for the SMTP process.
Is this just a matter of having to get in touch with the affected domains to request delisting internally?