Email Delivery Failure

Issue/Question

I cannot send a message to a person

An e-mail I sent to a colleague does not come through. 

Error: Delivery has failed to these recipients or groups:

Error: The recipient's email system isn't accepting messages now. Please try resending this message later or contact the recipient directly.

Error: We are unable to deliver your message to its intended recipient(s). Unrecognized sender email address:

Environment

• Microsoft Outlook

Resolution

1. Verify email address is valid
   1. Are there unneeded spaces
   2. Are there - or _ used correctly
   3. If it is a USD account
      1. Search Global Address List to verify correct spelling
   4. Not USD Account
      1. Reach out to the recipient to and verify the email address is correct
2. Verify recipient does not email forwarding setup to another email account