When you check your mail with Outlook using a POP incoming mail server you may get the following error:
Task 'servername.com-Receiving' reported error (0x8004210A) : 'The operation timed out waiting for a response from the receiving (POP) server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).'
The error message is the same in Outlook 2002, Outlook 2003, Outlook 2007 and Outlook 2010. Only with Outlook 2010 you might not get the error code (0x8004210A) but just the message.
One reason for this error could be a wrong port number for the POP incoming server. Particularly, if you haven't enabled encryption from the settings for the email account, but you have change the port to the encryption port number which for POP is 995. Either set the port number for the POP incoming server to 110, or enable SSL encryption and leave the port number to 995.
The other “usual suspect” that can cause this problem is your antivirus software or your firewall. For example, people using Norton Antivirus, Norton Internet Security, or McAfee products have reported this issue. Change the settings of your antivirus application to disable the scanning of emails, or, depending on the particular software, if there are such options, add the mail servers for the account to the trusted servers. You might also consider uninstalling the antivirus application temporarily just to test your email account again, in order to make sure that it's not the antivirus/firewall that's causing the problem.