Everyone's max receive size is set to 10MB (via default receive connector) I have created the following transport rule , to catch 10MB + attachments and redirect to support@domain.com, so the IT team can resize the images or documents and on-forward to colleagues. We still want the standard oversize NDR to be generated to the sender, so they understand the problem and hopefully address in future. This rule is not being applied during testing, even set priority to 1 and recycled the transport service. FYG, the receiving mailboxes ( support@domain.com )have been set individually to accept emails up to 30MB. The system is instead just sending the NDR and not redirecting the email with the oversized attachments. I'm sending the email from gmail.com account