Precision 3530 stoped working with TB16

Hello at all,

Since yesterday, my notebook stoped working with the TB16 Thunderbolt Dock. I'm running 2 additional monitors from the docking station, both are Dell monitors, a Headset, Mouse, Keyboard and some other stuff is connected on. Also the ethernet connection for my notebook is provided by the docking station.

The problem:
The monitors are flickering, sometimes each 20 minutes, sometimes each few seconds. Ethernet connection stoped working as well. Only charging or supply my notebook already works.

My trials to solve:
I've updated the TB16 with the newest firmware from Dell's webpage, and also updated all drivers on my notebook by "Dell Support | Updade"-software. A windows update also had been done, but I think this doesn't hurt for this topic.

Does anyone have an idea where my problem can lie on?

Thanks Flo