W 460 reports blockage ?

We have a W460 that gives indecations and bleeps to say inlet /outlet hose is blocked I have checked and cleared any (nothing to shout about ) dirt from the filter and checked in and out hoses .Did find brown snot in the soap tray inlet cleared this as much as possible the rechecked the machine with out the outlet hose in the extenal pipe this appeared to work placed the outlet pipe back into the externel pump and it failed .tried back into a bowl at low level as before ,Now all we get is the two lower LEDs flashing and we get the bleeping ?????