Hi,
Sending email to any gmail address is failed from mail id created in my account: dev at santanu.io. The mails are delivered properly in other email addresses such as outlook. I receive the following returned email:
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This is the mail system at host tommy2.heliohost.org.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<......@gmail.com>: host gmail-smtp-in.l.google.com[142.250.141.26] said:
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 [santanu.io] did not
pass 550-5.7.26 with ip: [65.19.141.77]. 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.
21-20020a631955000000b005142038a8c7si11885657pgz.291 - gsmtp (in reply to
end of DATA command)
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