Undelivered Mail Returned to Sender when i create local ticket

when i try to create a ticket from rt web interface its ok but i have an autoreply mail that sed “Undelivered Mail Returned to Sender” in the web interface
i get this error " <root@localhost>: Recipient address rejected: need fully-qualified address
(in reply to RCPT TO command)".
from any email i have to create ticket and mail delivred very fine and every think is ok
but only this problem when i try to create ticket from web interface
i’m using postfix and fetchmail with rt4.4.3
thanks a lot