09:16:13 2A9 Queuing deferred message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\send\sf0272f3.391
09:16:13 2A9 MSG 2249149 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf026b6b.349
09:16:13 2A9 MSG 2249149 Detected error on SMTP command
09:16:13 2A9 MSG 2249149 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249149 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 Building undeliverable message
09:16:13 2A9 MSG 2249150 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf026b89.350
09:16:13 2A9 MSG 2249150 Detected error on SMTP command
09:16:13 2A9 MSG 2249150 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249150 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 Building undeliverable message
09:16:13 2A9 MSG 2249700 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf02b635.858
09:16:13 2A9 MSG 2249700 Detected error on SMTP command
09:16:13 2A9 MSG 2249700 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249700 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 MSG 2249700 Deferring message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\defer\sf02b635.858
09:16:13 2A9 MSG 2249701 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf02b653.859
09:16:13 2A9 MSG 2249701 Detected error on SMTP command
09:16:13 2A9 MSG 2249701 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249701 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 MSG 2249701 Deferring message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\defer\sf02b653.859
09:16:13 2A9 MSG 2249702 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf02b653.860
09:16:13 2A9 MSG 2249702 Detected error on SMTP command
09:16:13 2A9 MSG 2249702 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249702 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 MSG 2249702 Deferring message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\defer\sf02b653.860
09:16:13 2A9 MSG 2249872 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf02c302.023
09:16:13 2A9 MSG 2249872 Detected error on SMTP command
09:16:13 2A9 MSG 2249872 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249872 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 MSG 2249872 Deferring message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\defer\sf02c302.023
09:16:13 2A9 MSG 2249873 Analyzing result file: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\result\rf02c302.024
09:16:13 2A9 MSG 2249873 Detected error on SMTP command
09:16:13 2A9 MSG 2249873 Command: owensville.k12.mo.us
09:16:13 2A9 MSG 2249873 Response: 450 Host down (owensville.k12.mo.us)
09:16:13 2A9 MSG 2249873 Deferring message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\defer\sf02c302.024
09:16:13 566 MSG 2249982 Processing inbound message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\receive\C47C20F4.452
09:16:13 566 MSG 2249982 Sender: bounce-4668227_HTML-223027605-297798...ail.cappex.com
09:16:13 566 MSG 2249982 Recipient: lcobb@owensville.k12.mo.us
09:16:13 566 Recipient is undeliverable
09:16:13 566 MSG 2249982 Converting message to SMTP: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\send\xf02c75d.129
09:16:13 566 MSG 2249982 Queuing message to daemon: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\send\sf02c75d.129
09:16:13 566 Recipient: lcobb@owensville.k12.mo.us
09:16:13 2A9 Queuing deferred message: GMAIL_S/SYS:\GDOMAIN\WPGATE\GWIA\send\sf02bb80.962
We keep getting 450 host down for owensville.k12.mo.us, which is our domain. Every now and then an email will be sent out, but it doesn't go through until 3-4 hours after it was initially sent. It has worked fine for years. The only thing that was recently done was that all users were removed except for two or three that still needed to send encrypted emails out to banks. I'm assuming that these issues started when that was done. I've recently been handed the responsibility of fixing this even though I have almost zero Groupwise administration experience.

Other than I know our mail servers DNS name is mail.owensville.k12.mo.us I really don't know much else. Where do I begin looking?