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Long_Tran_-_F's avatar
Long_Tran_-_F
Copper Contributor
Feb 05, 2024

O365 email bounce back from hotmail.com and outlook.com

Hi all,   Some days ago, we got a problem with sending email from our customer's domain to email of hotmail.com and outlook.com that we never met before.    When I tried to use their 2 different ...
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Dan_Snape's avatar
Dan_Snape
Steel Contributor
Feb 05, 2024
You'll need to look at the recipient side to figure out exactly why these are being rejected. Generally it's a misconfiguration of SPF, DKIM and/or DMARC. Google are getting closer to requiring all senders have message authentication configured.
  • DomP66's avatar
    DomP66
    Brass Contributor
    Feb 06, 2024
    Dan_Snape wrote:
    Generally it's a misconfiguration of SPF, DKIM and/or DMARC. Google are getting closer to requiring all senders have message authentication configured.

    Increasingly an issue for M365 Personal & Family customers who don't have any DKIM support from Microsoft.

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