[Mailman-Users] [ASK] Too Many Hops

[Reza Tarigan]

Hi everyone, I'm new to zimbra & mailman.
i got a problem when integrating mailman with zimbra.
I was follow tghe guide in wiki 

I got error when trying to send email to mailman at email_domain.com

5.4.0 Error: too many hops (in reply to end of DATA command)

Does someone know how to fix it or how to track  the error?
Sorry for my poor english..
thnx.