Particles are invisible when removing skybox in favor of material cubeMap

Hi, I have followed this link to gain skybox lighting effect with a transparent background - transparent skybox issue.
although it works for the model itself, if I have a model that includes particles system, the particles aren’t shown. particles can’t have an option for cube map so there is no way to light them using cubeMap.
Any suggestions?
Example - With skybox
Example - after skybox was removed

Is the background transparent for both projects?

Thank you for your help,
I did not change the background of the canvas yet, but the issue is not the transparency of the canvas, but the fact that without environment the particles are invisible.
Basically what i’m trying to achieve is using cubeMap only for lighting without showing the cubeMap itself.

Can you share the Editor project for the one with the skybox please?