We currently do not have any limits on the maximum size an email can be including attachments when sent out from Oracle B2C Service. However, outgoing messages are still subject to the limitations of the remote receiving server and each client or provider can vary. Therefore, it is recommended that the combined size of your message plus the attachment not exceed 30mb as it may affect the reliability with which messages are recieved. 

 

For more information regarding the maximum alotted size of file attachments please review Answer ID 280: Maximum size of file attachments