FastBloom is not supported on this platform?

When I try to use the Bloom (Optimized), on my camera, I get this error. The game is built for PC.

The shader Hidden/FastBloom (UnityEngine.Shader) on effect Player1Cam (FastBloom) is not supported on this platform!
UnityEngine.Debug:Log(Object)
PostEffectsBase:CheckShaderAndCreateMaterial(Shader, Material) (at Assets/Standard Assets/Image Effects (Pro Only)/PostEffectsBase.js:24)
FastBloom:CheckResources() (at Assets/Standard Assets/Image Effects (Pro Only)/FastBloom.js:40)
PostEffectsBase:Start() (at Assets/Standard Assets/Image Effects (Pro Only)/PostEffectsBase.js:71

What can I do to fix it?
Or can someone at least explain why it isn’t supported?

Thanks in advance.

@PunchButton_DEV, I met the same problem on unity 2018.3.b10. Is there any resolution?