Plumbing Issue

We are trying to de-winterize our 2005 Minnie Winnie 27P and cannot get water to pump to our bath or kitchen sink. The water flows fine to the shower, external shower, and toilet. We are stumped as we have never encountered this issue before. Been de-winterizing in the same way for many years. I do believe these rigs are set up to have water from shower and toilet go to black tank and the 2 sinks with no water go to the grey. Not sure if that is relevant.