550 Your HELO string is incorrect

Ok, I have been getting this error for a little while now. I only get it every now and then. I know it has something to do with my DNSZoneTemplate but I'm kinda at a loss as to what exactly needs to be changed. My web server's name is Web01 and my domain name is daycare.us. Can you tell me what I need to edit to correct this issue? Below is a copy of my current template.

Thanks, you guys ROCK!!!

$TTL 86400
@ IN SOA ns.{domainname}. {dnsemail} (
{serial} ; Serial
10800 ; Refresh
1200 ; Retry
86400 ; Expire
86400 ) ; Minimum

{domainname}. IN NS ns.{domainname}.
ns.{domainname}. IN A {dnsip}
ns1.{domainname}. IN A {dnsip}
ns2.{domainname}. IN A {dnsip}
dns.{domainname}. IN A {dnsip}
dns1.{domainname}. IN A {dnsip}
dns2.{domainname}. IN A {dnsip}
{domainname}. IN A {webip}
mail.{domainname}. IN A {mailip}
smtp.{domainname}. IN A {webip}
webmail.{domainname}. IN A {webip}
ftp.{domainname}. IN CNAME {domainname}.
www.{domainname}. IN CNAME {domainname}.
{domainname}. IN MX 10 mail.{domainname}.
{domainname}. IN TXT "v=spf1 a mx"


* IN A {webip}