Dell Server R340 does not find additional SSD Drives

Hi,

I have a brand new Dell R340 Server. I configures it with 2 x Dell 480 GB SSD and a Boss Card with 1 x m2  SSD.

The Chassis has space for 8 x Hot Plug 2,5" drives, 2 are used for the 2 x Dell SSD.

Today, I added 2 additional SSD's that I still had in my inventory. They are brand new Server SSDs with 1 TB. I wanted to add them in addition and for an additional Raid1 Volume. 

I installed them, when I power on the server the LEDs for the drives are blinking and inside DRaC I do also get an information that I added drives..removed and added again. Everything correct. But I can not configure them. They do not exist in Drac. My PERC H730P  controller looks like this

Steckplatz Status Zustand Kapazität Bus-Protokoll Hotspare PCIe-fähig

0 Online 446.63GB

1 Online 446.63GB

2 Empty Slot Empty

3 Empty Slot Empty

4 Empty Slot Empty

5 Empty Slot Empty

6 Empty Slot Empty

7 Empty Slot Empty

Does anyone know why ???