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Unified Messaging can't validate or generate a UM PIN for mailbox 'mailbox@keyman .com' : An error occurred
while accessing the user's mailbox. Details: The underlying connection was closed: An unexpected error occurred on a
receive.
This issue started recently not exactly sure when. We are running Exchange 2016 CU18
I cannot view the UM details for any UM enabled user in EAC. I also cannot enable or disable UM for any user.
Did anyone mess with the TLS settings on the Exchange Servers?
Yes. I'm checking that now. Thanks!
Awesome, let us know if that fixed it.
Yes, that fixed the issue!
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Hi @Anonymous ,
Have you made any changes to related settings recently?
1.Please check to see if “SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}” exists. According to my understanding, this system mailbox used by Unified Messaging in Exchange 2016 for storing UM console attending files and other information.
For more information you could refer to: Arbitration mailboxes
2.Please try to run the following command to check if you could view the detail information of UM:
Get-UmMailbox -Identity <> | fl
3.Please try to run the following command to enable the UM for user:
Enable-UMMailbox -Identity <> -UMMailboxPolicy <> -Extensions <>
In addition, please try to reproduce the issue. When the error occurs, check whether there is a related error log in the Event viewer. If it exists, please share it with us, please pay attention to is to cover your personal privacy information.
If the response is helpful, please click "Accept Answer" and upvote it.
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I have the same problem
Can view the UM properties of the mailboxes with Powershell command
Cannot enable it via powershell either. Same error.
I think it may be the TLS cipher suite selection. Another reply mentioned that and I did recently remove some weak cipher suites for a PCI audit scan. Testing that now.
Hi @Ivan R ,
Have you checked the state of the arbitration mailbox? Is it happening to specific mailbox or all mailbox?
Can you check for events MSExchange Unified Messaging to find out the inner exception?
Found an exception that there wasn't a compatible cipher suite. This is leading me to add back the cipher suites I removed recently for a PCI audit.
Testing now.
Told ya :)
Yep! It is now working.
can you write in more detail?
I was referring to my issue. If you find the same event log issue with no compatible cipher available then my solution will apply to you as well. I recently had changed the ciphers available on my exchange server to comply with a PCI audit. I used IIS Crypto to remove the weak ciphers. You can also use IIS Crypto to put them back in....
Problem with all mailboxes.