Using Windows Live Mail 2012 on WIN7 64-bit for more than a year. ISP is Verizon FiOS. Email addresses are @verizon.net.

Been receiving emails seemingly without issues, but...

Haven't been able to POST any outgoing emails now since (I believe) September 16th for either my main or sub accounts.

Indicator is a Norton Internet Security popup stating:

"Email Error. Your email message was unable to be sent because the connection to your email server was interrupted. Please open your email client and resend the message from the Sent Messages folder." Then the popup lists the from/to/subj.

I recompose and try to resend; same results.

I've rolled WIN7 back to September 6th thinking something got changed with the latest Windows Update, but results are the same.

I thought perhaps NIS was blocking the SMTP port, but same results when I turn off NIS and Antivirus. I don't see anything of significance in NIS's logs.

I am able to send/receive emails on these Verizon accounts using their webmail in IE or Chrome or Firefox.

Of course, Verizon's mini-app that sniffs out and corrects email problems does not know or care about Live Mail. Just Outlook and OE.

Ideas? Things to try? Thanks.