It is possible that the water is again so low in the tank that pump can't pick it up. Also, depending on where the pick-up tube is and what position you camper is situated, even though you may have water in the tank the water pump can't pick it up.
Does the pump now sound different then when water was flowing ?? That is an indication that it is not pulling water from the tank.
Chap , DW Joy, and Fur Baby Sango
2017 F350 Lariat CCSB, SRW, 4x4, 6.7 PS
2017 Grand Design Reflection 337RLS