You may be able to get it work by changing the IP address of the printer. This is a highly technical job, so you may need a LAN technician to help you to do this.
Currently the printer IP is 192.168.123.100, that is the default address, but that need to be change to 192.168.1.200. Assume that you have this ip address open. Give it a try.
download the PBM -80- EthernetSet.Zip and unzip it, then you get the Ethernet.exe
Disconnect the Internet, Attache the printer, now the network is not working anymore. run the Ethernet.exe and change the ip address to 192.168.1.200
You can only do this once.
Attach the printer to the Router now, Connect the computer back to internet, Run PBMDRVsetupv4.0 , printer installation by using 192.168.1.200 IP address Test the printer before you use it in the POS application.