Delivery has failed to these recipients or groups:
sanaekum@mitrphol.com
The email address you entered couldn't be found or is invalid. It may be due to a bad entry in your Outlook or Outlook Web App recipient AutoComplete cache. Use the steps below to clear the entry from the cache:
1. Click New mail.
2. In the To field, start typing the recipient's name or email address until the recipient appears in the drop-down list.
3. Use the DOWN ARROW and UP ARROW keys to select the recipient, and then press the DELETE key.
Delete and retype the recipient's address, then try sending it again.
For more tips on how to resolve this issue, see DSN code 5.1.1 in Exchange Online.