Having an issue and have scoured the internet for hours with no solution that works. We have Exchange 2003. There are a few domains in which we just cannot send email to. The queue shows "Small Business SMTP connector - xxxxxx.com (SMTP Connector)" In Retry. On the bottom of the screen it says "Additional queue information | An SMTP protocol error occurred" (xxxxxx.com being the domain in question) This just started happening the other day. Prior to that everything was fine. And it's only about 4 domains that I know of. My Event Viewer shows a lot of 9158 and 9159 errors when an email is sent to one of those domains. Search of the web provided no useful help for those 2 errors. 9158 Error states "(BASE IL INCOMING RPC(24) PROC 0) Thread created, type = 6 (see SBCDERR.H) (4) The message history for one of the emails shows in short SMTP Store Driver: Message Submitted from Store SMTP: Message Submitted to Advanced Queuing SMTP: Started Message Submission to Advanced Queue SMTP: Message Submitted to Categorizer SMTP: Message Categorized and Queued for Routing SMTP: Message Queued for Local Delivery SMTP: Started Outbound Transfer of Message Message transferred to through SMTP SMTP: Started Outbound Transfer of Message Message transferred to through SMTP SMTP: Started Outbound Transfer of Message Message transferred to through SMTP SMTP: Started Outbound Transfer of Message Message transferred to through SMTP Basically there's 4 emails stuck in retry. If I right click in Queues and Force Connection nothing happens. Any ideas why it only happens to a few domains?

SBS questions are usually best posted to an SBS forum because some aspects of SBS are different from Exchange. Do you have a firewall or other appliance between your SBS server and the Internet that might be "fixing" your SMTP sessions? Cisco PIX firewalls are notorious for that. Turn up SMTP protocol logging and see if there is anything useful to be found there.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

SMTP log shows this for one of them 2011-03-14 15:39:41 192.168.1.26 domain.com SMTPSVC1 ADRSERVER 192.168.1.25 0 EHLO - +domain.com 250 0 329 18 0 SMTP - - - - 2011-03-14 15:39:41 192.168.1.26 domain.com SMTPSVC1 ADRSERVER 192.168.1.25 0 MAIL - +FROM:<user@domain.com> 250 0 47 34 0 SMTP - - - - 2011-03-14 15:39:41 192.168.1.26 domain.com SMTPSVC1 ADRSERVER 192.168.1.25 0 RCPT - +TO:<enduser@enddomain.com> 250 0 31 28 0 SMTP - - - - 2011-03-14 15:39:41 192.168.1.26 domain.com SMTPSVC1 ADRSERVER 192.168.1.25 0 DATA - <ADRSERVEREpTX5V3Gyk00000014@adrserver> 250 0 141 705 453 SMTP - - - - 2011-03-14 15:39:43 12.9.139.96 OutboundConnectionResponse SMTPSVC1 ADRSERVER - 25 - - 554-smarthost.enddomain.com 0 0 23 0 1110 SMTP - - - - Changed a few things obviously.

If you are sure that you are sending to the correct SMTP host for enddomain.com, then the relay error is erroneous. It is said that some e-mail domains reject with that error code when your own server fails some sort of antispam check, such as an invalid reverse lookup PTR record for your server.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

I'm not convinced that the 554 you see here is what's putting your queue into a retry state. A 5xx error is "fatal" and would cause the message to returned as undeliverable, not retried. Look again, this time for 4XX status codes, or 5xx status codes that are returned for individual commands (e.g., you get a 5xx status code when you say HELO or EHLO). I see that you're sending the SMTP e-mail to your Exchange server from some other SMTP server in your own network (IOW your Exchange server is acting as a SMTP relay). Your server then sends the message to the machine "smarthost.enddomain.com". But you've only shown the log entries for the message as it's receivd by your server. You've omitted the conversation your server has with the smarthost.enddomain.com machine (12.9.139.96) that ended with the 554 status code. That's the stuff you want to look at!--- Rich Matheisen MCSE+I, Exchange MVP