Email Recipient Resolved to another Email Address in Exchange 365

[JD_Hort]

When an email is sent to one email it gets resolved to another email address on the same domain.

In the Exchange Admin Center Message Trace there are two records:

1) Recipient One is redirected to Email Two 

2) Delivered to email address removed for privacy reasons

This is happening to more than one Sending mailbox but we haven't found any other recipient email address that it's occurring to.

I have checked End User Inbox Rules and Rules in Exchange Admin Center, Mail Flow, Rules and there is nothing that is doing this.

Our issue is I can't find why/where this redirection is happening.

We have a hybrid Exchange 365 environment with an internal exchange server syncing to the Exchange Online.

We have a full 365 suite including Dynamics and we use Outlook 365 thick client applications.

The only unknown for me is the First Email Address has left the destination organisation so they may have a redirection to email address.

Thanks in advance.

[#2]

What does a message trace show?

[#3]

Hi Vasil,

Thanks for replying.

I mentioned in the original post what the Message Trace said.

Here it is from the report. I have changed the actual real Sender and Recipient email addresses.

2022-08-04T03:26:28.8466356Z

Sender

Recipient1##Receive, Resolve;Recipient2##Deliver

"Regarding Service Record #15,835 Re: Milestone report submission- Upload issues with delivery portal"

27824

<1378358157.5303.1659583588222.JavaMail.svc_sysaid@SServiceDesk>

24b18599-181f-43da-79b4-08da75c91e97

203.54.133.70

Originating

To_DomainForcedTLS

Normal

Regards,

@JD_Hort 

[#4]

@JD_Hort Hi, I was wondering if you ever got a solution to this issue.  We have a similar issue but it is only for one recipient email.  Similarly, I cannot identify where in our Exchange this redirection is specified

Thanks in advance,

David