Unable to connect over ethernet after some hours of runtime (Colibri iMX6, WEC2013 BSP 1.2B6)

At the moment we are testing a new Product that we want to release in the next time.
After some hours of runtime the device can’t be reached anymore via ethernet.
If you try to send a ping to this device you did not get a answer, but the device is still
runing and senidng data via rs485.

Has someone an idea why the ethernet port stops working?

We are using an Colibri i.MX6 Duallite with an Windows Embedded Compact 2013 with BSP 1.2B6.


We had some issues related to ethernet in the past, but the latest drivers (included in 1.2b6 image) passed our internal tests.
Can you please tell me what is the state of the ethernet icon on the taskbar, if you have a screen connected to your device?
Is it connected or shows the red cross, meaning no connection?
Can you also enable serial debug messages?
To do that press space and then x on the serial boot console and then enter:
set dbg.serial 1
save dbg
This should print some additional messages, can you check if something appears when the device stops responding?