Message Size Limits (Legacy users)

The maximum message size is 10MB for outgoing email messages sent through SMTP on and  This limit applies to the entire size of the message, which includes the message body, headers, and any attachments.

If you absolutely need to send a message that is larger than 10MB, you can send a request via email to to have the message size limit temporarily increased on the server. However, large files should not normally be sent as attachments in email messages. Instead, please consider using OneDrive to share files.

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