[StAPF] 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: m.mueller.binz(a)gmail.com host gmail-smtp-in.l.google.com [2a00:1450:4013:c08::1a] SMTP error from remote mail server after end of data: 550-5.7.26 The MAIL FROM domain [zapf.in] has an SPF record with a hard fail 550-5.7.26 policy (-all) but it fails to pass SPF checks with the ip: 550-5.7.26 [2a00:1f78:af02:2::32]. To best protect our users from spam and 550-5.7.26 phishing, the message has been blocked. Please visit 550-5.7.26 https://support.google.com/mail/answer/81126#authentication for more 550 5.7.26 information. j3-20020a170906278300b0096f6faaaa93si3661663ejc.223 - gsmtp