You're using the wrong domain name to display your DNS records. The following command is incorrect:
You're using the FQDN of the server instead of the domain name, the correct format is:
I'd suggest you completely remove Zimbra with the "./install.sh -u" then fix your DNS A & MX records and confirm your hosts and resolv.conf files are correct. Go to the
Split DNS and read what's needed for your configuration the check your set-up by running
all the commands in the 'Verify...' section of that article. When you've done that and it's all correct the install Zimbra again.