Some email messages are not delivered when you set the MessageRateLimit parameter in a throttling policy in an Exchange Server 2010 environment

Consider the following scenario:

• You create a throttling policy that contains the MessageRateLimit parameter in a Microsoft Exchange Server 2010 environment. For example, you set the value of the MessageRateLimit parameter to 1.
  
  Note The MessageRateLimit parameter specifies the number of email messages that can be submitted to transport every minute.
• You apply the policy to a user.
• The user sends email messages at a rate that is greater than the limit that is set in the MessageRateLimit parameter by using Microsoft Outlook 2010 in Cached Exchange Mode. For example, the user sends two email messages in one minute.

In this scenario, email messages that are sent after the limit is exceeded are not delivered later and are moved to the Sent Items folder unexpectedly. Additionally, the user does not receive a non-delivery report (NDR).

In the example that was mentioned earlier, the second email message is moved to the Sent Items folder. Additionally, the email message is not delivered later.

Note If the user sends email messages by using Outlook 2010 in Online Mode or by using Outlook Web App, the excess email messages are also not delivered later. However, the second email message is moved to the Outbox folder or to the Drafts folder.