System crashes when using ethernet
I thought the upgrade my home internet with a new 1Gbit connection. I also moved to TP-Link M4 in router mode.
The first is connected to the main router en connects to a TP-Link switch (TL-SG108)
The second is on the first floor and connected to the earlier mentioned switch
The third is on the second floor and connected to also to the earlier mentioned switch. The second port has a switch on it.
Without the switches powered on it all works fine.
However when I power on the switches the main switch works just fine; however, the first and second floors directly go to a red flashing light and remain in that condition. They are running the most recent firmware.
I also have a set of S4; Those are located in the garage, and some other places and not wired. However I have the same issue if I use them wired. instead of the M4.
What could cause this issue? What is wrong with my ethernet setup?