Today a user called me because they could not send a large attachment (apparently 8 MB).I increased their send limit to 50000KB in Mailflow Settings (Mailbox properties).Send still failed.I increased send size on the Send Connector to 102400 KB (just added a zero since we needed to move fast).I OK'ed everything. Get-* commands showed that setting was effective (apparently).Yet user could not send and ended up faxing a hard copy.So what went wrong?Why could I not allow this user to send the document?Did I need to restart a service?Could it have in fact been a mail server upstream (or downstream or wherever) that was bouncing the message back?I did not see the error message myself - user was elsewhere - contacted me by phone.

Was he using MAPI or IMAP/POP3?What did the NDR say? Perhaps the bounce was from the receiving party? You can also do message tracking in EMC\tools

Well, its unknown without more info.1st, when you change the mailbox send limits, they do not take effect immediately unless you restart the information store service. The default is 2 hours unless you have modified that setting:http://technet.microsoft.com/en-us/library/bb684892(EXCHG.80).aspxMailbox Size Limits Are Not Enforced in a Reasonable Period of TimeWhen changing the limit on a connector, you should restart the Hub Transport service so that takes immediate effect as well, but its change will be applied generally in about 15 minutes if you do nothing.Finally, when sending to the internet, you need to account for MIME encoding on a SMTP message which is generally 30-40% of the original message size.For a 8 MB message, that means the send connector limit should really be around 12MB. ( though you set it much higher of course)But this is all speculation, since we do not have the actual NDR or message tracking logs.

Thank you both.The user was using Outlook 2007, so MAPI.As I said, I did not see the NDR.I'm aware of the message tracking function so I might take a look at that - I believeyou can filterbyNDR.

I see this has been answered, so I guess that was the problem. But I wanted to point out it could also be the receive connector if using SMTP to send mail instead of MAPI. Outlook of course can do this if not using MAPI which is what i was checking on. :)Mike Crowley: MCT, MCSE, MCTS, MCITP: Enterprise Administrator / Messaging Administrator