Steps to  rid of errors when sending e-mail from Outlook to a contact group:

• Open Outlook.
• Click Account Settings from the Tools menu.
• After selecting the destination POP3 account, click Change.
• Select More Options from the drop-down menu.
• Select the Advanced option.
• Increase the server time-out setting gradually.
• Examine your Internet connection.
• Accessing Suspicious Emails Should Be Avoided.
• Examine your antivirus settings.
• Outlook should be reinstalled.
• Change the time-out settings on the server
• You can manually extend the time it takes for your Outlook application to connect to the server.

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