We don't have enough information. We don't know anything about your turntable or cartridge. If, for example, it is a MC (moving coil) cartridge, instead of the more common MM (moving magnet) cartridge, then that would explain it, because MC cartridges typically have very low outputs. With a MM cartridge, it could either be a problem with the cartridge, the turntable (unlikely), the wires connecting your turntable to the receiver (unlikely), or the receiver.