I have Windows Live Mail 2011 configured identically on two PCs for POP3 access to an Outlook.com account.  One pc is running Windows 7, the other Windows 8.1.  The configuration works fine (can send and receive) on the Windows 7 pc.  On the Windows 8.1 pc, the setup doesn't work (can't send at all, and receives intermittently and unpredictably).

The Windows Live Mail error message on the Windows 8.1 pc is :

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Unable to send or receive messages for the *** Email address is removed for privacy *** account. The connection to the server has failed.

Server: 'pop-mail.outlook.com'
Windows Live Mail Error ID: 0x800CCC0E
Protocol: POP3
Port: 110
Secure(SSL): Yes
Socket Error: 10060

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The configuration on both systems is:

'Servers' tab:

 Incoming mail (POP3): pop-mail.outlook.com

 Outgoing mail (SMTP): smtp-mail.outlook.com

 My server requires authentication: Checked

'Advanced' tab:

 Server Port Numbers:

  Outgoing mail (SMTP): 857

   This server requires a secure connection (SSL): Checked

  Incoming mail (POP3): 995

   This server requires a secure connection (SSL): Checked

 Leave a copy of messages on server: Checked or unchecked, this setting has no effect on the connectivity failure

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I don't see how ISP port blocking can be the issue (as suggested by Socket Error 10060), because these two systems are using the same internet connection.  Also, this is my initial effort to migrate to outlook.com from my ISP's proprietary email domain, which works OK, but is costing me extra money every month and is not a good long-term strategy.  My multiple ISP-proprietary email addresses are NOT exhibiting any connectivity issues; only the new outlook.com addresses.

Any idea what is going on here?