When using the online recommendation functionality provided by YAP Tracker, an email request is sent to the recommender when you add their name to your application. Sometimes, for various reasons (accidental deletion, spam etc.) the recommender doesn't see the email.
To resend a recommendation request:
Before resending, make sure that the recommender has added firstname.lastname@example.org to their safe list. If they still don't see it, ask them to check their spam folder. Finally, ask them if they have an alternate address.
When you resend a recommendation request, a confirmation email is also sent to you. That email contains a link and a code that you can provide to a recommender that will allow them to submit their recommendation if they still don't receive the email.