Error while downloading email using Windows Live Mail 2012

I have recently upgraded to Win7 and Windows Live Mail 2012. I have multiple email accounts that I set up in Windows Live Mail. I have previously used Windows Live Mail (earlier versions) for this same process with no problem. However, I have set up my Yahoo account in WLM and I am getting an error message. Error message is as follows:
It says:

Unable to send or receive messages for the Yahoo (swilson933) account. Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

Server: 'plus.pop.mail.yahoo.com'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: POP3
Port: 995
Secure(SSL): Yes

I have checked and double checked my configuration for setting up yahoo mail and I have deleted the account and settings and recreated it and it would download emails initially but then the next day when I would open Windows Live Mail, it would not update with current messages.

I have checked and changed firewall settings - with no change in response.

Any suggestions regarding this issue would be so greatly appreciated as I am so frustrated as to why this is not working for me at this point.

Thank you,
Shona

Robin9 - thank you very much for the suggestion. Yes, I have tried that, I have verified that all settings according to yahoo are consistent with what they recommend, but it still is not sending/receiving the way it should.