Are both your iPad and your Mac on the same network?
If so, then next step is to check your firewall settings on your Mac as per this support document
if that doesn't fix it.. see the following support doc about TouchOSC
Finally, if you are running Little Snitch, disable it and test.... If it works with Little Snitch (LS) disabled then you must find the seeting in LS that is preventing connection between LPX and Logic Remote and remove it.