Solution:

There is added latency when making an Ethernet to Serial conversion. If there is an option in the software for controlling a polling rate, or data speed, try slowing the speed down to see if it makes a connection. If using the ESR90x series, make sure that the Red and Green LEDs turn ON when the software opens the Virtual Com port. If they do not turn ON, then the software is not opening the connection. Try putting a PC on the serial connection of the ESP90x /ESR90x, and open a terminal Emulator program. When the Software is opening a port, see if you can see any data coming through.