Miele W504 plus water protection system activated

Hi, I'm first time poster here and would appreciate if someone can help with this issue. Basically, I have this oldish miele that has never failed us and now it is coming up with check water inlet and check water drain pipe warning lights, both together towards end of cycle. It came back after few washes having cleared it once by tilting machine slightly to deactivate sensor, which I found out about from online help.

Now the question I have is if this happens again, could it be fault with the water protection activation sensor that brings up these warning lights to protect excessive water leakage? I mean, both times this has happened, I haven't seen any visible water spillage other than maybe whatever slight spillage there may be in the built in tray under the machine and rocking the machine to deactivate hasn't resulted in water spillage either. Are you able to shed some light as to why this sensor has cut out twice and may possibly trip again