R2308WFTZS and Xeon Gold 6128

Hi experts,

we set up a system based on Server R2308WFTZ with Dual Xeon Support. We selected 2x Xeon Gold 6128 for our purpose.

However we are not able to get the system running. We installed both CPUs and 96 GB ECC ram (Kingston Ram KVR24R17S8K4) in total.

The fan of the power supply start running for a short amount of time (~0.5sec) and nothing else happens.

If just the first CPU installed, the system starts as expected.  If the CPU of second socket is installed in the first Socket it starts too. As soon as a CPU is installed to the second socket the system does not start.

So in my opionion the CPU can´t be the problem. Also swapped RAM without any effect.

What can I test? Do I miss something?

Thanks a lot,

Christian