This morning outbound e-mail stopped functioning completely. No changes have been made recently except Windows Updates on our Windows servers the night prior. Inbound e-mail, from external sources, is working just fine. I'm very new to Zimbra and am at a loss on what I can do to troubleshoot this. I've rebooted the Zimbra server 3 times now to no effect.

I'm not sure what info I need to list and I'm unsure of how to find the Zimbra version I'm using.

Any help would be appreciated,