If you cannot connect Ctrl for iPad to ENTTEC LED Mapper (ELM). Firstly, check your iPad’s network settings to ensure that both your iPad and ELM PC are in a similar IP range with the same SubNet and Remote HTTP is enabled within Settings -> Remote within ELM (a SubNet of 255.0.0.0 is recommended on both your iPad and ELM PC). – To confirm connectivity you may wish to ping your iPad from your PC's command prompt.
Ensure your HTTP patch you are using for the ELM module is raw:
To rule out anything network related, create an HTTP fader to control ELM and ensure ports are not being blocked with connectivity and firewall settings.
If this still doesn’t work, try a different port other than
80 to communicate over (update ELM’s HTTP port to reflect this).