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AUTH not working anymore on Exchange 2016



Last weekend, I did apply an update to the Exchange 2016 server. Since then, it appear that the "AUTH LOGIN" dosent work anymore on CRD.


I'm not sure if I need to change something on the CRD side or on the Exchange side, but some of my Distribution Group are giving error now "550 5.7.133 RESOLVER.RST.SenderNotAuthenticatedForGroup; authentication required; Delivery restriction check failed because the sender was not authenticated when sending to this group".


I can see the user is authenticated, since he's using "Client Proxy" when using authentifications and "Default Proxy" when not autenticated.


Any idea where I should look ?


And no, I can't disable the authentication for those group, I want to restrict who can send email to this group! :)


1 comment

  • 0
    Sebastien Plante

    As FYI, I fixed the problem.


    Open ADSI


    Configuration > Services > Microsoft Exchange > DOMAIN > Administrative Groups > Exchange Administrative Group > Servers > Protolcs > SMTP Receiver Connectors

    Properties for the "Client Proxy", in Security, select "Authenticated Users", check the box "Accept Any Sender", "Accept Authentifcation Flag" and "Accept Authorative Domain Sender". Mine was missing "Authentification Flag".



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