I added the MX records for our Gmail Business Account to our DNS zone over 24 hours ago. When someone is logged into Gmail and sends an email to someone else in our company, the email arrives in their Gmail account. However, when someone is logged into their Zimbra email and sends email to the same email address, it arrives in that person's Zimbra account. Why is this happening and how can I make the email go to their Gmail account like it's suppose to?
Zimbra checks locale settings (LDAP) before MX records. You will have to set up your domain in Split Domain mode to achieve what you want. Click here to read how to set it up.