Many network connection and communication problems result from incorrect device names, incorrect IP addresses, or other attribute value errors entered into the Site Management Portal UI or into the UI of the associated network devices. If the NAE attribute values do not match the values entered in the devices connected to the NAE , the NAE and associated devices may not establish network connections or communications.
Check the device names, IP addresses, gateway, subnet masks, ports, baud rates, and other network parameters in the Site Management Portal UI. Also check the servers, computers, and field devices connected to the NAE , and ensure that the attribute values are correct for each computer or device.
For example, communication between a Site Director and an NAE could be lost after downloading the network engine with SCT. This may occur on a network where device name resolution is not implemented. To resolve this communication issue, log in to the NAE after the download and change the Local Site Director field back to the IP address of the Site Director. Within minutes after you save this change, the engine comes back online to the Site Director.
See Determining the NAE IP address and device name for a network connection and Verifying Ethernet network communications (Ping).