Delivery not authorized, message refused

Actually nothing issue before I reused the exchange certificate at my exchange server.

Here is how do I issue the certificate 

get-exchangecertificate
copy all thumbprint normally 4.
get-exchangecertificate -thumbprint (paste thumbprint) |new-exchangecertificate
I did it for all thumbprint and finally remove old 
get-exchangecertificate -thumbprint (paste thumbprint) |remove-exchangecertificate

And I do not use any 3rd-party anti-spam. BTW, I am not that experience user for those exchange administration however I have fixed it. 

Windows Server 2003 R2, Exchange Server 2007

Thanks in advance for any help.