Problems with unitys Particle: Fire_Complex from the Standart assets

Hello dear Community,

i am making a game on an Island in the Ocean. Unfortunantely it went not so good as i expected. I added a small campfire from cylinders with wood textures, put them on the ground, and dragged the Particle System on it. It looked nice, BUT all of the shadows in my scene were gone and the complete graphics were bugged (waterproadvanced got the watersimple look) Then i switched to the mobile particle system, and it worked.

I dont know what could be wrong because i am new to unity.

Please help!!!