ORLANDO, Fla. -- Avengers: Endgame is the most anticipated movie of the year. So it's no surprise that thousands of Marvel fans flocked to websites like Fandango Tuesday morning when tickets went on sale.

Demand was so high, however, that Fandango, AMC Theatres and other ticketing sites experienced technical issues. Many fans were met with error messages while trying to buy tickets.

Some were kicked out of AMC's app. On Fandango, fans faced wait times of over an hour-long just to purchase tickets.

"We want everyone to be able to grab their Avengers: Endgame tickets, but it looks live we've gotten Thanos' snap," AMC Guest Services wrote on Twitter. "We're working on getting things back up and running, and in the meantime, please keep trying our website and our partners sites!"

And once fans were able to get onto the sites, many of the tickets for opening night were already gone.

Fans were not happy, with many sharing their frustations on Twitter.

Avengers: Endgame is set to hit theaters on April 26. Last year's Avengers: Infinity War made over $2 billion at the box office. Based on how eager fans are for the next installment, Endgame is likely to top that.