Which server is "mail server.domain.com"? That server is trying to send the message to the next hop server, and that's the one throwing the NDR.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hi, I did configure the "Message delivery properties" of global settings and set the send & recieve size to be 2M. In this case, someone tells me that you have to configure other settings to let OWA work. Do you have any experience to configure the OWA to send BIG email? If so, please give me suggestion. Many thanks.

I don't think that's coming from OWA. The NDR is coming from an SMTP server.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Can you help to confirm if I need to configure any others to make OWA work when sending bigger email?

Hi, I did increase the send & recieve size on the globaal settings of ESM and then all client can send "BIG" email to ourside users. But there is another issue on OWA, they want to have the same behavior when using OWA to send email. My question is: what's the default size for owa to send external mails? and How can I make it be bigger? Thanks.

Please share the error message or non-delivery report message you receive when trying to send an "oversize" message.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Your message did not reach some or all of the intended recipients. Subject: Sent: 30/08/2011 17:17 The following recipient(s) cannot be reached: jay7336@hotmail.com on 30/08/2011 17:17 There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <mail server.domain.com #5.5.0 smtp;552 #5.3.4 message size exceeds limit>

Hi Human_Bing, Per my knowledge, I never heard a message size limit base on OWA. As I know, Exchange 2003 can restrict message size base on: a. Global setting b. System policy c. Mailbox store d. per mail box e. distribution group f. virtual SMTP server g. connector More information about how to restrict message size limit http://www.msexchange.org/tutorials/set-size-limits-messages.html http://support.microsoft.com/kb/322679

Ok.....So I don't need to do any other thing for OWA? I'll update if it works.