Status Log - What is the source for this error

I am communicating with 13 Omron NJ and NX PLCs.
Sometimes I get communication errors -mostly related to NJ-models.

q1: When troubleshooting using Status/Log I find the attached message and I think its related to my issue. Is there any way of relating this message to the root cause? (When opening the Status/Device/Detail I dont get any related log.)

I’m not sure if this log message is coming from one of your NJ driver connections or something else that uses Netty, like an OPC UA connection, but it means the remote side closed the TCP connection. Whatever it was should start reconnecting automatically; that this shows up in the logs is mostly a nuisance.