554 5.3.4 Message too big for system

When an SMTP mail server responds to an attempted email delivery with:

554 5.3.4 Message too big for system
This indicates that the email message is larger than the per-message size limit for this server.

When this error occurs, the message has not been delivered. In this case it is a permanent error, and you should not try to send the same message again at a later time.

You can try again with a smaller message.