Mail delivery failed: returning message to sender

This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: newsletter@newslettercollector.com host mail.newslettercollector.com [136.144.140.124] SMTP error from remote mail server after RCPT TO:: 550 5.7.1 : Recipient address rejected: Message rejected due to: SPF fail - not authorized. Please see http://www.openspf.net/Why?s=mfrom;id=newsletter@newslettercollector.com;ip=168.195.204.51;r=newsletter@newslettercollector.com