Mail delivery problems lately

  • Resolved plimsb99

    (@plimsb99)


    5 months ago

    We noticed within the mail log, that some mails fail to send lately. This didn’t happen in the past and started about 2-3 weeks ago as far as I can see.

    Other mail are beeing sent without problems so this is not a general problem.

    For the mails not beeing sent the status reads:
    “” does not match the expected structure for a DNS hostname, ” does not appear to be a valid URI hostname, ” does not appear to be a valid local network name”

    We are using Microsoft Office365.

Viewing 2 replies - 1 through 2 (of 2 total)
  • Plugin Support M Aqib Khan

    (@aqibkhan9)

    4 months, 4 weeks ago

    Hello @plimsb99 ,

    Thank you for reaching out and for sharing the error details. We’re truly sorry to hear that you’ve encountered this issue.

    The message: “does not match the expected structure for a DNS hostname, does not appear to be a valid URI hostname, does not appear to be a valid local network name” is returned by Microsoft Office 365 when an incoming SMTP connection or message contains an empty or malformed hostname value.

    Although this setup may have worked previously, Microsoft has been gradually enforcing stricter SMTP validation rules over the past few weeks. As a result, emails that contain invalid or blank values in fields such as the SMTP EHLO/HELO hostname, sender domain, or Message-ID domain may now be rejected by some Office 365 mail servers.

    Could you please share your diagnostic test report & share if emails triggered through any specific plugins are failing with this error?

    Looking forward to your response.

    Plugin Support M Aqib Khan

    (@aqibkhan9)

    4 months, 2 weeks ago

    Hello @plimsb99 ,

    We hope you are doing well.

    We are marking this thread as resolved due to inactivity. If you encounter any further issues, please feel free to open a new thread.

    Have a great day!

Viewing 2 replies - 1 through 2 (of 2 total)

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