Undeliverable mail

When I send a email to someone. I receive the following undeliverable mail message that says

“yeo.lay.leng@i-weekly.com.sg on 05/05/2004 8:00PM

The recipient was unavailable to take delivery of the message
The MTS-ID of the original message is: c=US;a= ;p=JAY GEE ENTERPRI;l=JGEXCHANGE-040505092741Z-12066
MSEXCH:IMS:JAY GEE ENTERPRISE:JG_DOMAIN:JGEXCHANGE 3499 (000B09B6) Host unreachable

Any advise?

thanks and regards,