Issues communicating with a Continuum controller after controller hardware replaced.
The replacement controller has been assigned identical IP address and ACCNet ID as the controller it replaced.
Cached ARP table at gateway device (Router, Switch) contains old MAC address for the controller.
Each controller has a unique MAC id that can not be changed. Network gateway devices use special tables to map IP addresses to physical MAC addresses and use the ARP (Address Resolution Protocol) to keep such tables up to date.
When a device is replaced, the cache ARP table in a router may for a while contain the physical (MAC) address of the old controller associated with the IP address, this will cause communication problems until the table is updated via ARP (Routers periodically update their ARP tables) or is manually flushed to force an update.
Wait for the gateway's ARP table to update or manually flush the table.