I recently installed a 2010 Outlook Client from Office 2010 Home and Business and it is accessing a 2003 Exchange environment. I began to get this error on larger emails being sent out and then the email would delete from the sent box leaving this in the inbox Your message did not reach some or all of the intended recipients. Subject: FW: Sent: 4/14/2011 5:18 PM The following recipient(s) cannot be reached: xxxxx@xxxx.com on 4/14/2011 5:18 PM This message could not be sent. Try sending the message again later, or contact your network administrator. The client operation failed. Error is [0x80004005-0xfffff9bb-0x000501]. Any thoughts?

Hi, It seems not a Outlook 2010 issue, Could you please try sending the same large E-mail with Outlook 2003 or Outlook 2007? If Outlook 2003 and Outlook 2007 are also unable to send the same large E-mail. I will suggest you checking the following options : 1. If the recipient E-mail address is right. Are you able to send an small E-mail to the recipient? 2. You can set message limits on the following objects: Global settings System Policy Individual mailbox Individual message limit Distribution list Public folder Connector Virtual SMTP Server More information: How to Set Size Limits for Messages Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.