[Cause]
A Modbus TCP master device attempted to connect to the robot Modbus slave, but the server has used all available connections. Under the Modbus TCP protocol, when a new connection request arrives and there is no unused connection, the oldest connection is closed and the new connection request is accepted. This alarm is a warning message and occurs only the first time this happens after power-on.
[Countermeasure]
Add connections to the Modbus TCP image.