DL360 G10 - Unsupported DIMM Configuration

Hi HPE Forum,

I have a DL360 G10 with 8 x 16GB DIMM Modules (815098-B21).

So I looked up the Population guidelines > https://h20195.www2.hpe.com/v2/GetDocument.aspx?docname=a00017079enw 

That tells me to install into Slot 3, 5, 8 and 10. And that's what I did for both CPUs

But I recieve:

Could someone please point me to what I am doing wrong?

Thanks in Advance

Markus