EWS Error: Unable to Connect to Server: [ErrorServerBusy]

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Example found in a crmex-log file

The error, displayed in the CRM Monitor, also appeared in the log file.

2012-01-16 16:10:42,118  INFO [CTP-uox #6689] [374875395] (AssignTo) Processing Opportunities
2012-01-16 16:10:42,275  WARN [CTP-uox #6689] [374875395] Service response error: [ErrorServerBusy] The server cannot service this request right now. Try again later.
2012-01-16 16:10:42,275 ERROR [CTP-uox #6689] [374875395] Error occurred subscribing to events.
Omni.Connection.Ews.EwsServerException: Unable to connect to server: [ErrorServerBusy] ---> Microsoft.Exchange.WebServices.Data.ServiceResponseException: The server cannot service this request right now. Try again later.



“[ErrorServerBusy]”, an Exchange system error, means that the Exchange server is too busy to handle the requests.

Immediate Corrective Actions

The Riva sync service needs to be stopped for an extended period of time to give the EWS server sufficient time to clear the conditions that triggered the Service response error: [ErrorServerBusy] error:

  • For Riva On-Premise:  In the Riva CRM Service Monitor application, STOP the service; or, in the Windows Services applet, STOP the "Omni Riva (CRM Agent for Exchange)" service.

  • For Riva Cloud:  Edit the sync policy, select the General tab, clear the Enable Sync Policy check box, and save the sync policy.

Leave the sync service or sync policy disabled for a minimum of two hours.  Re-enable data sync, and confirm that the error does not occur again.  If it does, disable data sync for a four-hour period.

Long-term Corrective Actions for Riva On-Premise

The long-term corrective action is to reduce the number of concurrent web service calls on the EWS service so that EWS throttling is not triggered.  This may vary, depending on which Exchange system Riva is connecting to:

For Office 365 Exchange Online (Enterprise) or Exchange On-Premise 2013 or 2010

Switch to using the EWS Impersonation method.  This greatly reduces the number of web service calls that Riva makes when syncing users concurrently.

To use EWS Impersonation:

  1. Assign the Exchange service account (configured in the Riva EWS connection) to use Exchange ApplicationImpersonation role permissions:

  2. In the Riva Manager application, select the Setup tab. In the right pane, double-click the EWS connection to Office 365 to edit it.

  3. In the Connection Details tab, set the Impersonation Method to EWS Impersonation.

  4. Save the EWS connection.

  5. In the Riva CRM Service Monitor application, RESTART the service.

For On-Premise Exchange 2013 or 2010 Systems That Need to Use Delegate Full Access Permissions

For On-Premise Exchange 2013 and 2010 systems that need to use Delegate Full Access permissions, Exchange administrators can choose to disable EWS throttling for the Riva EWS connection user (Exchange service account for Riva).  This option is not available for Exchange On-Premise 2007 or 2003 or for most commercially hosted Exchange service providers.

For Office 365 Exchange Online (Personal / Small Business), Commercially Hosted Exchange Services, and Exchange On-Premise 2007

For those Exchange environments, Riva administrators are limited to making changes in the Riva sync policies, as follows.

To minimize web service calls to Exchange:

  1. Reduce the total number of execution threads set in each sync policy to no more than "3".  For instructions, see The Connection Options Page:  Execution Threads.  If there are multiple sync policies enabled, reduce the  maximum number of concurrent execution threads consumed by all sync policies to "10".

  2. Set the sync interval between each full sync poll to a longer interval.  For example, if the interval is set to 10 minutes, set it to 15 minutes or 30 minutes.

  3. Clear the Check drop folders on the fast sync schedule check box.

  4. Configure Advanced Scheduling options to Ignore items with no relevant changes from Exchange and Ignore items with no relevant changes from CRM.

Applies to

  • Riva for Exchange using EWS connections

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