In the Add-On settings is the ability to setup one or more email addresses to send reports to. You can configure the same or different addresses for the successes and the failures. It is highly recommended that you at least setup a monitored email address for any possible failures to alert you to.
In the Add-On Configuration check the right hand side to make sure that valid email addresses are set to accounts that are monitored actively. Each daily sync (if enabled) will generate at least one email with the details of what was synced from your CSV file.