By default, Microsoft® Exchange 2010 and newer versions use client throttling policies to maintain a consistent performance profile for all users by tracking the usage of each Microsoft Exchange user and can enforce usage and bandwidth limits as necessary.
1. Office 365 (Exchange Online) does not allow customers to modify EWS throttling. For additional information, see Exchange Online Throttling and Limits FAQ. If sync service logs show the Exchange service was not responding, Riva made excessive attempts to connect and sync users. Recommended corrective actions include:
When using "Delegate Authentication", because the Riva Sync Service user synchronizes data between Exchange and the CRM on behalf of all users, Exchange interprets the requests as being above normal and applies the EWS throttling policy. Depending on your environment and the number of objects and users being synchronized by Riva, the EWS throttling policy can affect Riva's ability to sync data in a timely manner. For environments that require "Delegate Authentication", we recommend turning off client throttling for the AD/Exchange user that will be used by Riva to communicate with Exchange. Riva has built-in configurations that can be used to throttle the application itself internally.
For EWS connections on Exchange 2010 SP1 or newer, when using "Application Impersonation", the throttling is done on a per-mailbox target, not based on the "connection user" used by Riva to authenticate to Exchange. For these environments, Exchange throttling errors should be monitored during a deployment; however, disabling throttling is not recommended.
The following resources provide more information about Exchange throttling policies:
How to implement EWS Throttling
The following is the recommended procedure.
To apply a throttle policy with no limits on EWS usage to the Riva user:
The Riva sync policy includes a means to implement connection throttling by using execution threads.