If you plug it into DC, it won't be able to drive the rhinestone at all, eliminating the possibility that you plug it in incorrectly.
The rated power of a 2600W gasoline generator is around 2000W, which is more than enough to run rhinestones.
1 Use a multimeter to test the generator output voltage to see if it is normal, or use other electrical devices to test if the generator is working normally
2 Plug in your rhinestones in another power supply to test if there is a problem.
Chances are there is a problem with your generator