What to do if an error message appears when sending out e-mails using Outlook Express Ver.6.* and e-mails cannot be sent out?

Err Msg: Could not send the message as one of the recipients is rejected by the server

To resolve this symptom, change the settings of receiving and sending e-mails with the steps below:
1. Start Outlook Express, click the Tools tab and then click Options.
2. Click the General tab, disable the Send and receive messages at startup option and click the Send tab.
3. Disable the Send messages immediately option and then click the Connect tab.
4. Disable the Disconnect when sent/received messages option and click OK.

Next, send e-mails with the following steps:
1. Click the Tools tab and then click Send and Receive -> Receive All.
2. Click the Tools tab and then click Send and Receive -> Send All.

Note: If the time pre-determined by the network provider has elapsed or the network connection is disconnected after the completion of Send and Receive, the Send and Receive process needs to be repeated again.