On Tuesday, Bernie Sanders slammed New York s closed primary system after a frustrated voter vented to him about not being able to vote.The voter, 21-year-old Mike Cantalupo of Massapequa, New York, went up to Sanders and explained how the system had not only confused, but ultimately failed him. Cantalupo said that he d been trying to enroll as a Democrat since last spring, but couldn t succeed because he was told that by the Department of Motor Vehicles that his paperwork was lost. Then, when he tried to register again in December, he was told that the deadline for a change-of-party in New York had passed (the deadline is October). Despite all of his efforts, he couldn t change his registration and was ultimately prevented from casting his ballot. He told Sanders: New York has terrible voting laws. Right now I m trying to do everything I can to get my vote cast for [Sanders]. I can sign a court order and an affidavit and whatever I need to do, and I m going to do that, but it shouldn t be this hard to vote. Sanders heard Cantalupo s concerns and nodded. He agreed that  No, it should not be  this hard for people to vote. He added: Today, 3 million people in the state of New York who are independents have lost their right to vote in the Democratic or Republican primary. That s wrong. You re paying for this election; it s administered by the state, [and] you have a right to vote. That s a very unfortunate thing that I hope will change in the future. You can watch Cantalupo s conversation with Sanders below:WATCH: @BernieSanders tells independent voter by Times Square:  You have a right to vote  https://t.co/1dXt1G3Cauhttps://t.co/PztjYBywWU  ABC News Politics (@ABCPolitics) April 19, 2016Because of these issues, 3 million people that are registered outside of Republican or Democratic parties may not be able to vote in the primary. Jose Ruiz, a polling site coordinator, estimated  I d say 30% are not registered, even though they thought they were. And it wasn t just registration that voting New Yorkers had trouble with. In other cases, polling places were moved without adequately notifying voters, and some polling sites were set up hours later than their scheduled time.Despite all of the issues and setbacks, Sanders is still hopeful. Continuing to bash the primary problems that voters are now referring to as  sabotage,  Sanders said: We re feeling very good. If there is a large voter turnout   despite the impediment of 3 million people not being able to participate   I think we re going to do just fine. Compared to the rest of the United States, New York is generally low in voter participation regardless of whether it s a local or national election. Open primary states, or those with same-day registration, have much higher turnouts.Featured image via Spencer Platt / Getty Images