What parameters need to be set to remotely access two Digi One SP devices on the same LAN?

How do I configure two separate Digi One SP devices for remote access on the same LAN? Both Digi devices are connected to separate ports on the same router. I can remotely access one but not the other.

Can you also ping the one you can not access remotely. You should be able to open a browser if you can ping it.
Below is the DigiOne SP User’s Guide:
http://ftp1.digi.com/support/documentation/92000326_D.pdf