Hello everyone.
I would like to know if anyone ran into the same issue and was able to find out the solution or an explanation of such behavior.
We use D365 CRM On-Premise 8.2.2.0112. Our email system is Exchange 2016 On-premise.
Earlier, we configured Server-Side Synchronization for a shared mailbox named support. This mailbox is available for our support engineers and is used to receive support requests from users and customers. Though, as a shared mailbox it is available in Outlook Desktop Clients, we decided to configure email forwarding to personal mailboxes of these engineers. This forwarding is configured on Exchange server. So, when an email is sent to support mailbox it appears there and in engineers' mailboxes simultaneously. This is used to reduce the time needed by any engineer to get familiar with the request because they are continuously monitoring their personal mailboxes and may not notice the email in the shared mailbox. In addition, when an email arrives into the support mailbox D365 creates a case and sends some notification emails. This configuration is working fine when users' mailboxes are not being synced with D365 CRM.
This year we have upgraded our Exchange 2013 servers to Exchange 2016. This allowed us to start using Dynamics 365 App for Outlook. One of the requirements is to use SSS for the user's mailbox. I have enabled SSS for one of the mailboxes and this mailbox passed all checks. After that I enabled D365 App for Outlook and it is working almost fine in OWA, but not in Desktop Outlook Client.
On the next morning we received an email to support mailbox and it has been forwarded to the mailbox with SSS enabled. After that I noticed an warning on the Mail Server Profile page, stating that an unknown error occurred during the sync of this email in the engineer's personal mailbox. This error does not give any clues but it has the following additional information: UnknownIncomingEmailIntegrationError -2147218683. I was able to locate this email in the support mailbox, but a case was has not been created.
We are going to move to D365 App for Outlook and we need to create cases from emails sent to support mailbox. These are manadatory requirements. I may remove the forwarding of these emails, but it would be great if we can continue with that.
So, now I am wondering how to resolve that and looking for an explanation. I understand that our configuration may be unsupported or maybe I missed something, but I am not able to find any useful information. Any help is much appreciated.