For a short time we hosted another entities email on our Exchange 2013 Server as part of a migration strategy.  We have moved them to their own Exchange server. For the sake of explanation i'll call ours aus.com.au and theirs show.org.au

I removed (or so I thought) the config for the show.org.au, but when we attempt to send email to show.org.au our exchange server comes back with an NDR because it cant find the recipient in our server.  Interestingly if the Recipient didnt exist on our server, the email is sent to the show.com.au's server, so it only effects those addresses that were hosted for a time on our server.

Clearly the show.org.au domain is still recorded somewhere in the Exchange 2013 config, but I havent been able to find it.

Get-AcceptedDomains - returns aus.com.au and aus.local

Get-ReceiveConnector configs show no clues

Hello

outlook not use cache emailaddress?
try send email with telnet to "wrong" emailaddress if go out try delete emailaddress from outlook /nk2/

Hi,

Have you checked the address book policy for show.org.au too and make sure that it is removed. Also verify the smtp address of the mailboxes, to see if they have the smtp entries of show.org.au  still

Thanks Guys,

All references to the Hosted domain have been removed from the EAC

• Accepted domains
• Email Address Policies
• Receive connector
• Resource mailboxes
• Shared mailboxes
• Contacts
• Mail flow rules covering Disclaimer, re-routing ex staff emails to new recipient, SCL reset on email from their scan-to-email devices
• Mailboxes
• I have viewed the Config changes history and checked each of the items referred to in the config change log no longer exist

In AD there was an OU used to create dynamic Address Lists, this as well as all the domain accounts have been deleted

Please post the exact NDR users get and also try from OWA and see if you get a NDR.