Exchange Admin Center lists ".com" and "Local" in accepted domains list. What is the correct fix?

Question

Hello All,

A 3rd party vendor set up a Microsoft Exchange migration some years ago. We are trying to troubleshoot some Health mailbox routing issues in which the smtp addresses for the health mailboxes list both ".com" and ".local" as the SMTP addresses. From another forum question we have asked - we understand that ".com" needs to be set as the default SMTP address. 

But when we look at the Exchange Admin Center it lists ".com" and ".local" in accepted domains list, even though ".com" is set as the default domain. I understand this is not a good practice and so my question is what are:

1) Would it be correct to delete the ".local" domain from the accepted domains list?
2) Is there something else that I need to put in this list besides ".local"? Such as "ad.domain.com"?
3) Would the reason ".local" is in the accepted domains list be why our Health mailbox is reporting routing errors? ("Inbound proxy probe" errors).
4) If the above is true, and I should remove ".local" from the accepted domains list, what is the correct way to say the exchange settings and remove this? Just run a backup of the server and then just delete the object from the list? Any caveats? Is it just that simple and I am over-complicating this?

Any help would be greatly appreciated.
Sincerely,
Brian

Answer 1

Hi Brian.

According to your description, I suppose that domain.local is your AD domain and domain.com is your mail domain.
If I misunderstood it, please feel free to correct me.

1) Would it be correct to delete the ".local" domain from the accepted domains list?
According to this link: Default domain

The default domain is also associated with the default email address policy which cannot be removed.

2) Is there something else that I need to put in this list besides ".local"? Such as "ad.domain.com"?
Sorry I am not quite sure what "ad.domain.com" is.
If you have other mail domains to receive emails, you should add them to the list.

3) Would the reason ".local" is in the accepted domains list be why our Health mailbox is reporting routing errors? ("Inbound proxy probe" errors).
I noticed you have asked a question about this issue: Undeliverable Inbound proxy probe message troubleshoot

I think the cause of the issue should be the monitoring mailbox having an incorrect email address.
Thus it cannot route the messages correctly.

Here is also a similar case for your reference: Undeliverable - Inbound Proxy Probe (Exchange 2013) - healthmailbox email address using wrong domain

4) If the above is true, and I should remove ".local" from the accepted domains list, what is the correct way to say the exchange settings and remove this? Just run a backup of the server and then just delete the object from the list? Any caveats? Is it just that simple and I am over-complicating this?
As mentioned in my former reply, you cannot remove the default domain but can only add new domains and set them to be the default domain.

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Answer 2

Thank you Kael Yao for all your insight and help. I very much appreciate it. I am trying to narrow down where the issue is with the 'Inbound proxy probe' error message. Yes, one of the addresses is incorrect which lists both smtp for domain.local and SMTP for domain.com for the Health mailboxes. The email filter research indicates it doesn't like the ".local" address. So in my research I was wondering if the accepted domains tab where "domain.local" is listed was the source of where the email address were being assigned .local and com addresses for the health mailbox because I don't see .local listed in AD under the Health Mailboxes -only domain.com. But you have shown me that the accepted domains list is not where I would fix the issue - thank you. I will also review that link you sent me about changing the address for the Health mailbox

One more questions please:

I noticed domain.com and domain.local are listed as smtp addresses under the Default email address policy. Could this be the reason why domain.local is being listed in the Health Mailbox along with domain.com? Would removing domain.local here be the fix for the inbound proxy probe errors?

thank you,
Brian

Answer 3

As an update- I have made some DKIM adjustments to and that has helped, but I am still getting the inbound Proxy probe messages.

thank you,
Brian

Answer 4

Based off of the link you sent I see the statementL

"The Monitoring mailboxes email addresses should only have the domain suffix of the default accepted domain. If that gets messed up, deleting them and restarting the Health Service on each MBX server should recreate them correctly."

So it appears I should manually change the secondary smtp address to .com instead of .local, correct? Please confirm.

https://social.technet.microsoft.com/Forums/en-US/323db794-fe77-4ae9-a2ea-82de293de5e1/undeliverable-inbound-proxy-probe-exchange-2013-healthmailbox-email-address-using-wrong-domain?forum=exchangesvrgeneral

thank you,
Brian

Answer 5

When I run this:
Set-Mailbox -Identity HealthMailboxxxxxxx -EmailAddresses @{remove="xxxxxxxxxxx.domain.local"}

I get this error message:

"WARNING: The command completed successfully but no settings of 'domain.local/Microsoft Exchange System Objects/Monitoring Mailboxes/HealthMailboxxxxxxxxxxxxx' have been modified."

Is this a permissions issue?

thank you,
Brian