Latitude 5580 RAM upgrade problem

Hi,

I have a Dell Latitude 5580 with 8GB RAM (one module). I wanted to upgrade to 32 GB and ordered two 16GB modules from crucial.de. Of course I checked the compatibility before placing the order.

I put in the two new modules and the laptop didnt boot anymore (No Memory Detected). I even dont get to the BIOS.

I tried several combination with these results:

Conclusions:

• The modules are compatible with Latitude 5580, otherwise they wouldnt work in any constellation
• Both modules are intact, because they both work (atleast in Slot 2)
• Slot 1 seems to be the problem. But on the other hand if Slot 1 would be damaged, it wouldnt work with the old 8GB-Module, right?

Any help or suggestions would be appreciated.