Toss us a domain so we can try from ours. Go off list if need be. From: listsad...@lists.myitforum.com [mailto:listsad...@lists.myitforum.com] On Behalf Of Steve Ens Sent: Tuesday, October 7, 2014 4:02 PM To: exchange@lists.myitforum.com Subject: Re: [Exchange] 421 4.2.1 Unable to connect errors
Yes, already tried that. I can do a MX lookup, but cannot telnet to the server. Also getting this in the logs Error Code: 10061, Error Message: No connection could be made because the target machine actively refused it That seems to point to us being blacklisted, but I come up clean on the mxtoolbox tests. On Tue, Oct 7, 2014 at 2:48 PM, Kennedy, Jim <kennedy...@elyriaschools.org<mailto:kennedy...@elyriaschools.org>> wrote: What are the domains? Could be bad bounces from spam to non-existent domains Your server can not contact them, so it tried alternates either in dns or per the RFC’s (for example A record of domain.com<http://domain.com>) and that failed. So it is still trying. Do an MX lookup from your transport server to verify your DNS is working. Then try telnet port 25 from the transport server to that IP to verify connectivity. What do you get? From: listsad...@lists.myitforum.com<mailto:listsad...@lists.myitforum.com> [mailto:listsad...@lists.myitforum.com<mailto:listsad...@lists.myitforum.com>] On Behalf Of Steve Ens Sent: Tuesday, October 7, 2014 3:42 PM To: exchange@lists.myitforum.com<mailto:exchange@lists.myitforum.com> Subject: [Exchange] 421 4.2.1 Unable to connect errors Odd errors in my mail queue. Just started appearing yesterday. Most mail gets sent, but from certain domains I get these errors. "Attempted failover to alternate host, but that did not suceed." Anyone see this before? Exchange 2010 on Windows 2008 R2.