Exchange 2007 send connector does nor respect Maximum message size (sometimes...)

Question

Hi to all
We have 9 email server, 5 Mailboxes, 2 CAS and 2 HT, We began to have problems to send and receive from internet; so I checked the queues and I discovered that some users are sending messages with a size greater than 16 MB, althought internally can send
until 40MB, if they send externally, only until 16MB.
I revised all the configuration:
Organization Configuration/Hub Transport/Global Settings/ Maximum send size (KB):40960
Server Configuration/Hub Transport/HT01/Receive Connectors/Default HT01/Maximum message size(KB): 40960 (only this server can send outside, the other server is in spare)
Organization Configuration/Hub Transport/Send Connector/SendMailOuside/Maximum message size(KB) 16386
We send by an Smart host that is used only by the HT01 to a Symantec server.
With this, we have this situations:
In the queue, I see some users are sending emails with a size more than 16MB outside the organization, I revised their configuration and the "maximun send size" is clear the checkbox (just like my account), the weir is if I try to send an email
with a size more than 16MB, I got the message: "#550 5.3.4 ROUTING.SizeLimit; message size exceeds fixed maximum size for route ##", this is not sense because their account configuration is the same like mine, so the Exchange must not let
them to put the email in the queue...
If between internal users try to send an email with size more than 16MB, this is allowed and it's send without any problem
So I don't know where is the misconfiguration, is permited to send mails with size less than 40MB internally, but externally only until to 16MB, but I din't know why the Exchange system let some users to send (or at least put in the queue) this kind of messages,
my account is in the same DB like the other users...
I hope to be clear in the description of the situation, maybe a patch or some thing, the HT server has the January patch and in april will be applied the last patchs.
Doc MX

Answer 1

Hi DocMX,
Thank you for your question.
We could run the following command:
Get-TransportConfig | FL max*size
Then, we could check the send connector by the following command:
Get-SendConnector | FL Identity,MaxMessageSize
We could run the following command to check an individual user maximum size.
Get-Mailbox <username> | FL Name,Max*size
In my solution, we could rebuild the user profile that those users could send emails more than 16MB to check if the issue persist.
We could also restart the service of “Microsoft Exchange Transport”.
If there are any questions regarding this issue, please be free to let me know. 
Best Regard,
Jim
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Jim Xu
TechNet Community Support