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Strange issue here. Started the migration to Exchange 2016 from a single server Exchange 2010 deployment, followed this six part techgenix guide https://techgenix.com/migrating-small-organization-exchange-2010-exchange-2016-part3/ (haven't decommissioned the old server as there are some old mailboxes that need to be archived) - everything seems to have gone well, but after migrating most of the users to the new databases on the 2016 server. A few of the users (so far) are complaining that after a period of time Outlook randomly stops sending their emails. Email will get stuck in the outbox, it will send if send/receive is pressed, but it won't be saved in the sent items folder, mail that was opened won't appear as read, autocomplete entries wont populate, etc.
Mail flow works perfectly through OWA, it seems to be an outlook connection issue. The test exchange connectivity website reports that autodiscover is working properly, however.
If they exit outlook and open again, it may enter the same state immediately or will work for a period of time before having issues again. It always reports that it's connected on the lower right, however.
Does anyone have any idea what could be happening?
Have you restarted the AutoDiscover App pool on he 2016 servers once the mailboxes are moved to 2016?
Hi Andy,
Thanks for the reply! Yes, I've done that after each group of mailboxes were migrated to 2016. Outlook isn't in a disconnected state, in fact it says that it's connected but mail will stay in the outbox and the autocomplete list wont populate. They can press send/receive to get the message out of the outbox, but it wont save it to sent items. Alternatively, if they exit outlook and go back in, it will send, but then the problem arises after a few minutes. Strange.
I should mention that I have a computer at a remote location (different account) that I can't reproduce the issue with, so it seems to be an issue with the domain joined computers (they're connected via site to site vpn to the server) doesn't matter if they're using internal dns or, as a test I set one workstation to use public dns servers.
Is there a load balancer in the mix here?
Hi Andy,
No load balancer, straight connection from the domain joined computers (via vpn to the data center, all traffic allowed).
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Hi @Joey D ,
These events can be safely ignored because they don't adversely affect functionality and are by design. For more details: DCOM event ID 10016 is logged in Windows
For further troubleshooting, here are some troubleshooting steps you could refer to and narrow the issue:
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Hi @Joey D ,
How is your issue going? If you have any questions or needed further help on this issue, please feel free to post back. If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well.
Hi Joy,
The issue still persists for users that are using domain joined computers, but the issue seems to resolve once I recreate the outlook profile for the user. It take a couple of logins after the profile creation to resolve, however. Very strange behavior.
I was under the impression from the documentation and other posts by users that profiles would not have to be recreated during migration. Is this normal?
Hi @Joey D ,
In general, we don't need recreate outlook profile after migrating from exchange 2010 to exchange 2016, In some cases, Outlook prompts some errors after migrating mailboxes from Exchange 2010 to Exchange 2016. Trying restarting the autodiscover application pool and check if the issue continues. If it doesn't work for you, you need to recreate outlook profiles for them, since the pre-migration settings for the Autodiscover service that connects Outlook with Exchange are still cached in the registry of the Outlook profile currently in use.
Here's a similar thread for your reference: Recreation of Outlook Profile needed after Mailbox Migration 2010->2016
I don't know if it's relevant but I'm seeing a ton of these errors in the event logs of the 2016 server. I also see dcom errors in the 2010 server.
Log Name: System
Source: Microsoft-Windows-DistributedCOM
Date: 4/13/2022 4:56:58 PM
Event ID: 10036
Task Category: None
Level: Error
Keywords: Classic
User: DOMAIN\LWSERVER11$
Computer: EX.domain.local
Description:
The server-side authentication level policy does not allow the user DOMAIN\LWSERVER11$ SID (S-1-5-21-537193806-524895414-1911729130-1014) from address 192.168.0.2 to activate DCOM server. Please raise the activation authentication level at least to RPC_C_AUTHN_LEVEL_PKT_INTEGRITY in client application.