Troubleshooting Tip: FortiMail does not allow messages over 10MB

[mpuente]

Description	This article explains why the FortiMail does not allow mails over 10MB, those are being rejected, and how to avoid it.
Scope	FortiMail.
Solution	FortiMail was configured to allow emails over the 10MB size limit, but it is not allowing them to pass. There are 3 places in the FortiMail configuration, where the message size limit can be defined: At domain level, under Domains -> Domain Name -> Advanced Setting -> Other -> Maximum Message Size:  In the Session Profile assigned to an IP policy under Profile -> Session -> Profile Name -> SMTP Limit -> Cap message size: Note:  For outgoing emails, only the size limit in the session profile will be matched.  For incoming emails, the size limits in both the session profile and domain settings will be checked. If there is no session profile defined or no IP-based policy is matched, the default size limit of 10 MB will be compared with the size limit in the domain settings. In the content profile associated with the recipient policy that matches the message under Profile -> Content -> [Content profile] -> Scan Option -> Maximum attachment/message size): FortiMail will use the smallest size defined in the three settings.