Usually this is solved by charging correctly and switching on in the right order. Walk through the steps below.
Place the discs and remote in the case and charge them for 2 hours. Charging is complete when all four lights on the case are solid green.
Take the discs and remote out of the case, then press one gel pad firmly onto each disc. Leave everything switched off for now.
Press and hold the M button on each disc until it beeps. Only switch them on, do not press + or − to change the mode.
Press and hold the M button on the remote until the display lights up.
If one disc is not turning on, place it in the other charging spot in the case. Check whether the disc charges there.
If the disc switches on and seems to work, but you still don't feel anything, swap its gel pad for another one and see if that solves it.
You can now start your ReliveX session.