I created a scene using HDR, but when I render it, white spots appear in the image. When I use Denoise, there is distortion in the image. Isn’t there a way to solve this differently?
More samples might help, both with the dots and the distortion if you want to keep using denoise.
Those are most likely the problem known as “fireflies”. This happens because there is a combination of small light sources and sharp reflections.
This means that some rare rays of light will find the small bright spots on the reflective objects and create a bright pixel. This isn’t a bug, those bright pixels are just incomplete patterns of light that would eventually turn into a beautiful result if enough samples were used.
Cycles has some settings to minimize the problem: “filter glossy” and “clamp indirect”. By default, those settings are set to something that would prevent fireflies pretty well, so I’m guessing you changed them?
Filter glossy’s default setting is 1, which should do a nice job. Clamp indirect is set to 10, though that number is a bit on the low side and might reduce your scene’s lighting noticeably, I like to use 30 as a starting point.
If this isn’t the problem, I have an other idea that might be at fault here. Do you have light sources encased in glass materials? If yes, you would want to disable the shadows on those glass pieces, as Cycles doesn’t do glass shadows very well.