The throttling policy for user BENEXCHANGE2010\sescsvc01 prevented the creation of subscription for 6 user(s). Increase the "EWSMaxSubscriptions" throttling policy and retry. List of users who were not provisioned can be found at following location:
NOTE: The server name above is different depending on the name of the computer SESC is installed on.
SESC has encountered the EWS maximum subscription throttling policy. See Exchange Client Throttling policies. The EWS subscription could not be created. Since the EWS subscription is not created spam submitted to the folder is not processed by SESC.