I've found your project. Possible reasons of your problems:
1. Check IP address in settings. Your IP address looks like a global address. Does your PLC have such address?
2. Try to change "Request type" in your server ("Facebook Generic") settings from "Maximum registers" to "1 pointer registers". iOS devices (iPad and iPhone) have only this request type possibility. Maybe your PLC can't response to other types of requests.
Best regards,
Ruslan