Dit krijg ik terug in mijn e-mailclient:
This message was created automatically by mail delivery software.A message that you sent could not be delivered to one or more of itsrecipients. This is a permanent error. The following address(es) failed: mja.rust@gmail.com host gmail-smtp-in.l.google.com [142.250.27.26] SMTP error from remote mail server after pipelined end of data: 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 [desli.nl] did not pass 550-5.7.26 with ip: [82.215.18.102]. 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. lc9-20020a170906dfe900b0096a7839c72bsi4057679ejc.700 - gsmtp
