Sent email but no recipient receive any email

[joe1205630]

Dear All,

I'm using OpenEMM 2011 and my computer is window XP. OpenEMM is work normally until i click the [send] button yesterday.
I don't know why that no recipient receive this email. but the [Distribution status:] show it have just sent 25,839 email.
On the other hand, testing email also have this problem.

Here the screen showing:


Does any body can help me to find out or teach me what can i do of this?
I'm sorry that my english is not very good. if you want more details of this problem, you can reply and ask me.
Many thanks.

[joe1205630]

Hi All,

after checking the /var/log/maillog, I have find this msg as below photo. Does anyone know how to fix this problem?