554 Transaction failed Reject due to policy restrictions

Reason

Your email is malformed. The message contains at least one bare Line-Feed (LF) (%x0a) or Carriage-Return (CR) (%x0d) character.

RFC 5322 2.3.: "CR and LF MUST only occur together as CRLF; they MUST NOT appear independently in the body."

Solution

Please change your email text or update your email client software so that your emails don't contain a single LF or single CR character. CRLF (%x0d %x0a) as line break must be used.