My work is testing Zimbra on CentOS 6 to possibly use to host for customers. I ran into something that has been tough to find a good answer on. After the installation was complete, I wasn't able to send/receive mail on test accounts. Under the admin console under the service tab it shows a red X next to MTA. This may or may not be a really dumb question but I'm guessing that's my problem and I have no idea what the cause is based off of the google searches I did. If anyone can help it would be great! Thanks.