Exchange 2016 – Fail to Send Email to newly created MailContact


“Fail” LED=550 5.7.136 RESOLVER.RST.SenderNotAuthenticatedForRecipient; authentication required; Delivery restriction check failed because the sender was not authenticated when sending to this recipient.

In this post i will go over the option of removing the setting “Require that all senders are authenticated“.

In Exchange 2013 this can be removed by logging into the Admin Console > Recipients then select the mail contact and click edit. Remove the option “Require that all senders are authenticated”

However in Exchange 2016 this option is not available in the Admin Console and this needs to be done via Exchange PowerShell.

For this Example i will set the “RequireSenderAuthentionEnabled” to false on a Mail Contact.





Shaun Hardneck
ICT – Systems Manager
I see myself as somebody with broad experience in all aspects of IT Infrastructure, Technical Support and Network Solution Design , with my main focus on Microsoft Server Technologies . Experience in IT consulting in the Corporate Industry.

I see Myself as an Hard worker that tries to deliver the best at every task or project i receive.

“You can never plan the future by the past” Edmund Burke

Future Goals is too Grow a Low Cost reliable IT Support Service Desk.

Specialties: IT infrastructure and Microsoft Solutions and Office 365 Designs and Systems Support.

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