Controller lost ethernet communication without configuration changes

Hello guys, I have a SNAP-PAC-R1 controller. The controller has a fixed IP address and was running fine.
A ping test to the static ip address reply a good communication with 0% loss.

However, recently it will disconnect and shows unable to connect when use PAC terminal. And unable to ping to the same IP address. Preforming power cycle would bring the controller back temporary and will loss the communication again.

Do any of you guys experienced this situation?

Seems very odd to me that both PAC Term and PING stop working…
Could it be a bad cable?