Just set up an account with Sympatico and was told to uncheck "use authentication". When I got to my outgoing setting, I also had to choose whether or not to use SSL (Secure Socket Layer). I opted out as I believe this is what Aliant said to do. Is it unwise to not use authentication and SSL? When I first set up the account, I kept getting an error back when trying to retrieve mail due to the fact that I selected "use authentication".

You don't have an option (typically) whether or not you can use authenication/SSL for sending a receiving message, its mandated from your provider (ie Sympatico).