Try the trigger on a working input using the same cables that are currently plugged into a responsive channel.
Try plugging the trigger into a different adapter cable that is known to work.
At a low volume plug the trigger into an amplifier (again start at lowest volume) and tap for an audible response.
Try plugging the trigger into a DAW at low volume and look and listen for visual/audible input.
If you get it to work and the trigger is functional then the problem is most like the adapter cable or the input is not set to piezo (Alesis, Mimic) or is a dedicated switch input (Roland).
Additionally, ensure that your cable both Harness Type or Removable Mixer Style for that channel of your module is in fact an instrument (not a speaker) cable and tested by moving to another input or by using an actual cable tester.
If using a Stereo input ensure that your cable input to the module is a Stereo cable and the input preset in the module is set to “Dual Zone”.