What type of coffee can I use in this machine, and are there any beans I should avoid?

The appliance has been designed to work exclusively with coffee beans — never put ground coffee in the coffee bean container. The use of oily, caramelized, or flavored coffee beans is not recommended, as this type of bean may damage the machine. Additionally, ensure no foreign objects such as small stones enter the coffee container, as damage caused by foreign objects is not covered by the warranty. (Pages 7, 5)