I regularly get people who try to send me emails with attachments bigger than 10MB. I'm aware that this exceeds the size limit.

HOWEVER:

I (the recipient) never get an error message email that an email couldn't be delivered to me, and the Sender never gets an error message that his email couldn't be delivered to the recipient.

In other words: Nobody ever finds out that something went wrong - the email is just lost.

This isn't expected behavour, is it?

Thank you for looking into this.
Thomas