Reporting-MTA: dns; smtprelay04.ispgateway.de

Action: failed
Final-Recipient: rfc822;peterknoll@gmail.com
Status: 5.0.0
Remote-MTA: dns; gmail-smtp-in.l.google.com
Diagnostic-Code: smtp; 550-5.7.26 This mail is unauthenticated, which poses a security risk to the
 550-5.7.26 sender and Gmail users, and has been blocked. The sender must
 550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,
 550-5.7.26 DKIM checks did not pass and SPF check for [dachdeckerei-repenning.d
 550-5.7.26 e] did not pass with ip: [80.67.18.16]. The sender should visit
 550-5.7.26  https://support.google.com/mail/answer/81126#authentication for
 550 5.7.26 instructions on setting up authentication. 3-20020a05600c248300b003f81cad20f6si142117wms.82 - gsmtp