By default, system emails come from a no-reply email address. This type of email address can sometimes be marked as spam or junk depending on your organization or each individual user's spam/junk settings.
First, check your spam and junk folder for any messages regarding your application. If you do have a message in your spam please mark the message as valid in your main client and white list or allow the email address the message is coming from.
If you are still not receiving email notifications from the system please contact the school or district you are applying to.