Hi,
thanks for the quick response. Okay by dropping down the metalness everything becomes brighter. It´s okay to go ahead now.
But I am still wondering why the image is not showing up in the background, I hoped it would be reflected on the surfaces.
I thought this is related the problem mentioned in How do you use enviorement maps?
Because the same error message pops up as long aradiance is enabled. And maybe the HDR is not compiled correctly.