Wouldn't it be fairly simple to add a 3rd Custom notification option to allow the user to choose this? Backend system(s) would then need to delete the message(s) that were emailed. Since deleted messages are archived for retrieval, if the emailed attachment failed, the user could check deleted messages to retrieve them. It may be difficult to know that the message with the attachment never arrived, but this could be accounted for by use of an automated monthly message from RingCentral to the user indicating the number and type of messages automatically deleted. Yes, it is possible that this report message may not be received either, but knowing you were supposed to get it may alert you to the fact that you are not getting the messages with attachments, in addition to the monthly report.