People were very eager to get their hands on Roger Federer's commemorative coin after it went on sale this week.
Demand for the coin was so high that it caused the Swissmint's website to crash.
"We had 2.5 million clicks. It was too much for the shop to handle," Swissmint CEO Marius Haldimann told Paul Macpherson of ATP Tour.com.
"We expected and planned for high demand, but we never imagined it would be this big. When Roger posted a link on his social media channels, the website immediately had problems due to all the traffic. Some fans could access the shop but could not finish the order. Others could not get onto the website."
The Swiss government announced Monday that it was producing a 20-franc silver coin with the tennis star's image on it, marking the first time it's created a commemorative coin for a living person.
Swissmint sold 15,000 of the 35,000 coins available during the pre-sale, and the remaining 20,000 are expected to sell out quickly once the website returns to full functionality. Another 40,000 coins will be released in May along with a 50-franc gold coin.