Emails with attachments will not download in Windows Live Mail 2011 on a Windows 7 Home Premium 64 bit PC

Any emails with an attachment will not download and it keeps the emails that came in from last email download until the email with attachment tries to come in from downloading.  I get the following error message:  

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

Server: 'POP3.frontiernet.net'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: POP3
Port: 995
Secure(SSL): Yes

I have Norton Anti virus on the computer.  Disabling it does not correct the problem.  I have gone to Windows Live Mail safety Options and unchecked "Do not allow attachments to be saved or opened that could potentially be a virus". and that did not solve the problem either. 

I can send emails with small attachments.  I cannot send multiple photographs at once.

How can I get emails with attachments to download?