All outbound emails are limited to a size of 50 MB. This size includes both attachments, and the recipients list (the more recipients the larger that size becomes). For example if an email contains an attachment with a size of 50.5 MB, and the recipients list is .6 MB, the email will not send and remain in the outbox.
Incoming mail items are also limited to a size of 50 MB.
What Is Next?