There are no connections between the modules/devices and the controller, even though I have plugged them in.

Trolmaster uses RJ-12 hardwired cable connections (with a straight-through configuration) for all devices and sensors. Make sure you are using the same standard of cable as Trolmaster's cable. Double-check the cables and the Y-splitters. Look for loose connections or any signs of moisture/corrosion on the pins. Try connecting the module/device directly to the controller device port. If it works well when connected directly, then there is likely a problem with the cable or Y-splitter. If the module/device still has no connection after the steps listed above, then it could be a problem with the controller device port or the module/device itself. All devices have a 3-year warranty so as long as they are not physically/water damaged, you can get a replacement by emailing tech support on support@trolmaster.eu. Also send the serial number and a copy of the purchase invoice.