This error message started last night around 5:20PM. Before then, I had NO PROBLEM with sending and receiving RoadRunner emails through Windows Live Mail, which I access on my computer and allow all email content to remain on my hard drive. I suspect that someone (Windows Live Mail? McAfee?) did an automatic update and suddenly something that worked (outgoing mail) for two years just stopped. There have been no changes to my email account information.
Error Message received every time I try to send an outgoing email (incoming emails are coming through just fine) since 5:20pm last night: