I checked with Icybox as I was also planning to fit it with a 4TB SSD. The limitation is the USB 3 connection, which is limited to 5V/900mA +- 10%. That means you can't use SSDs with more than 4.5 watts power consumption. The Corsair MP400 8000GB already has a power consumption of 5.1W in standby and 6.5W in operation according to information here at Digitec. The case does not support Power Delivery, so it probably has the 900mA limitation even on a PD USB port. So the problem is not the 8000GB but the 6.5W power consumption.

That was the case with me too, I sent it back.