plc comms issue

I am currently having an issue with 2 cmore screens coming from a slc 504. The comms is feed from dh+ to ethernet by a net eni card nd from there to a startix 8000. The issue is i will randomly lose comms to the screens due to plc time out. I can connect remotely to the screens so i know they are still on the network. Also i can see they are comunicating to the stratix.
It appears they drop out going to the plc from the NetEni.
This is a random thing and the fixes for it are random as well. Sometimes i can remove the power from the cmore and it starts working again sometimes i can remove the ethernet and same thing, it works. Most of the time though we have to leave it alone and it works itself out.
I am fairly good with program debugging and troubleshooting with the plc but networking was never my strongest suit. It seems to me that i am getting packet loss/data traffic jams when communicating between the stratix/plc.