Supported email service configurations for server-side synchronization

Depending on your customer engagement apps (Dynamics 365 Sales, Dynamics 365 Customer Service, Dynamics 365 Field Service, Dynamics 365 Marketing, and Dynamics 365 Project Service Automation), installation, you may be deciding whether to use server-side synchronization or the Email Router/Outlook synchronization. This following table lists what is supported by server-side synchronization for each type of installation. Later in this topic, you can read about the scenarios that aren't supported by server-side synchronization.


  • The information here includes the POP3/SMTP and IMAP/SMTP systems supported by Microsoft. Although other POP3/SMTP and IMAP/SMTP systems might work with Customer Engagement (on-premises), those systems were not tested by Microsoft and are not supported.
  • Outlook on the web is not supported in a hybrid deployment: Customer Engagement (on-premises) with Exchange Online.
  • You can create two different email server profiles: one for online mailboxes, and another for on-premises mailboxes. Associate the mailboxes with the correct email server profile.
  • Manual tracking in Dynamics 365 for Outlook is not supported when a user's mailbox is configured to use server-side synchronization with the POP/SMTP protocol.
  • For Dynamics CRM Online 2016 Update 1 and December 2016 Update for Dynamics 365 (online), we support service encryption in Exchange Online with server-side sync.
Customer engagement apps deployment Email system Email synchronization Appointments, contacts, and tasks synchronization Protocol
Customer engagement apps - Exchange Online
- Exchange Server 2013 SP1
- Exchange Server 2016
-Exchange Server 2019
Yes Yes Exchange Web Services
Customer engagement apps - Gmail
- Yahoo! Mail

Using Exchange Online with customer engagement apps

If your company is using Exchange Online with customer engagement apps, note the following:

Customer engagement apps support server-side synchronization with Exchange Online in the same tenant in Microsoft 365 with Server to Server Authentication. Other authentication methods or settings are not recommended or supported, including:

  • Using credentials specified by a user or queue
  • Using credentials specified in an email server profile
  • Using Impersonation
  • Setting Auto Discover Server Location to No
  • Using an email server profile other than Exchange Online

Connecting customer engagement apps with Exchange Online in a different tenant (limited support)

Customers can connect to a Microsoft Exchange online deployment hosted in a different tenant. For more information, see Exchange Online cross-tenant authentication.


The following limitations apply to connecting cross-tenant:

  • Dynamics 365 App for Outlook is currently not supported.
  • Approval of Dynamics 365 mailbox records must be performed by a Global tenant admin or an Exchange admin of the primary tenant.

Unsupported email service configurations

Server-side synchronization doesn't support the following scenarios:

  • Packet inspection, transformation and manipulation of network traffic sent to Exchange from Dynamics 365
  • Network traffic interception not based on source IP address or server name (interception based on contents of a packet is not supported)
  • Mix of Exchange/SMTP and POP3/Exchange
  • Exchange Online profile mailbox with Exchange on-premises user. Use the Exchange Server (Hybrid) profile, associate the mailbox to it, then test and enable
  • Exchange Online profile mailbox with an Exchange mailbox that points to an external email server. Use the POP3/SMTP Server profile, associate the mailbox to it, then test and enable.
  • Creation of mass email marketing campaigns
  • Extensibility scenarios like extending EWS/POP3/SMTP protocols and creating custom email providers
  • Exchange Server 2010 SP3
  • Exchange Server 2003 and Exchange Server 2007
  • Server-side synchronization in customer engagement apps requires a POP3/SMTP email server that is also FIPS 140-2 compliant. Some email servers are not FIPS 140-2 compliant, such as MSN,, or Windows Live Mail
  • Multi-factor authentication isn't supported for customer engagement apps to Exchange Server (on-premises), and Customer Engagement (on-premises) to Exchange Online


We recommend that you don't use a mixed configuration of Outlook synchronization and server-side synchronization for appointments, contacts, and tasks in the same organization, because it may result in updated data not synchronizing to all attendees.

See also

Server-side synchronization
Set up server-side synchronization of email, appointments, contacts, and tasks