Outlook 2010 IMAP - cannot connect to server

Hi there. I have had an ongoing problem with a customers PC or more specifically outlook 2010.

The system is windows 7 x 64 with outlook 2010.

The problem is with outlook connecting to the yahoo server via IMAP.

I have tried everything I can think of and now I have completed a fresh install of windows and outlook. I have not installed anything else except for office 2010.

So I setup a new account in outlook with IMAP. The server settings are all as recommended:
Incoming Server imap.mail.yahoo.com
Outgoing Server smtp.mail.yahoo.com
Incoming Port 993 (requires SSL)
Outgoing Port 465 or 587 (requires SSL/TLS)
Username Full email address with @xtra.co.nz e.g. joe.bloggs@xtra.co.nz
Password

When completing, it seems to connect to the out going server OK and the outlook test message can be seen in the customers webmail, but I get the error: "cannot connect to server" or "your server unexpectedly terminated the connection" and no emails ort folsers can be synced. Works fine on his android smart phone. Error is also as per the attachment.

The service provider is Spark (Was Telecom NZ).

Any suggestions would be greatly received.

Thanks and Regards.
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