Thursday , June 11 2020

Transport Moderation Not working in Exchange 2010 – NDR says ”No arbitration Address for approval process”

User gets NDR – When the the mail has to be moderated by Exchange Transport


#550 5.2.0 Resolver.MT.NoArbitrationAddress; No arbitration address for approval process ##image


This is because of Missing arbitration mailboxes or Corrupted arbitration mailboxes

If you run the below command in Exchange management shell

Get-Mailbox –arbitration


You should see your arbitration mailboxes , If you see the above result

Then there is no problem with your arbitration mailboxes


If your are not seeing any arbitration mailboxes or you are seeing that your arbitration mailboxes are corrupted.

No wonder why Your Transport moderation does not work as expected and keeps generating NDR


You can recreate them , Even if they go corrupted


See –

How to recreate System Mailbox , FederatedEmail & DiscoverySearchMailbox in Exchange 2010


Arbitration mailbox The arbitration mailbox is used to store the original message that’s awaiting approval. By default, one arbitration mailbox is created for moderated transport during setup. It’s used for all moderated recipients. You can add additional arbitration mailboxes for load balancing purposes. If you’re using multiple arbitration mailboxes, you need to specify which mailbox to use for each moderated recipient.



All the mails which has to be moderated are getting stored in your arbitration mailboxes.


Most common issue on why this happens –

When you delete your default databases abruptly using adsiedit.msc or any other tools

Then you end up missing your arbitration mailboxes

Result of it –Transport moderation does not going to work

About Satheshwaran Manoharan

Satheshwaran Manoharan is an Microsoft Office Server and Services MVP , Publisher of Specialized in Office365 / Microsoft Exchange / Virtualization , Sathesh is an Messaging Expert supporting/Designing/Deploying many medium size businesses to large enterprises when it comes to Corporate messaging and Virtualization Infrastructure

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