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daniel.hettema@gmail.com (expanded from inkscape@dhettema.nl): host gmail-smtp-in.l.google.com[142.250.27.27] said: 550-5.7.26 Your email has been blocked because the sender is unauthenticated. 550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM. 550-5.7.26 550-5.7.26 Authentication results: 550-5.7.26 DKIM = did not pass 550-5.7.26 SPF [srs.dds.nl] with ip: [83.96.176.83] = did not pass 550-5.7.26 550-5.7.26 For instructions on setting up authentication, go to 550 5.7.26 https://support.google.com/mail/answer/81126#authentication a640c23a62f3a-a93c2a61647si928329466b.899 - gsmtp (in reply to end of DATA command)