Outlook sending attachements errors with TrendMicro

All of a sudden my client could not send large attachments. Got this error:
Sending' reported error (0x800CCC0B) : 'Unknown Error 0x800CCC0B'Task - Sending' reported error (0x8004210B) : 'The operation timed out waiting for a response from the sending (SMTP)

Outlook 2007 was installed along with Trend Micro Internet Security. It was timing out on the send. Found it to be the scanning of large attachments was the issue so I turned off the out going scanning and it worked without a hitch.

See images below:

If you don't want to disable this, then try increasing your server timeout in advanced settings of your email accounts. To do this go to the top toolbar, tools, account settings, double click the email account you wish to adjust, more settings, advanced.
See example:

Another timeout option could be due to your internet connection.
Run "ping -n 25 www.yahoo.com" to see how many packets you lose. If the percentage goes above 4%, it can start to be noticeable in web browsers and may cause some e-mail clients to timeout.
At this point you might want to have your IT professional look at this or call your ISP and let them know what is happening.

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