When e-mailing a large document from Neos, if there is an issue with the document size, Neos should give us a pop up of this. Outlook has a file size limit of 20 MB or less which causes Neos not to attach a file over this size. Then, it looks like the document has been sent even if it is not attached.
Neos needs to notify their users of this. Not everyone is going to be aware of this file size limit.