Please change the label to something like "common knowledge of life" or "household appliances" next time you ask this kind of question. As an amateur plant researcher, I see so many weird questions. I'm tired. . . . . .

This may be because the popcorn machine at your home is not warm enough. You can increase the temperature.

It may also be that the popcorn machine at your home has too much corn/too much ingredients. Many

It is also possible that the corn from the poster's home is too wet, so dry it before using it again

Of course, uneven heating is also possible.