The pump module has no input (velocity or torque) at the shaft. The system of equations is missing conditions needed to start the simulation.
Before you add any input though, consider using a simpler source block, like flow rate source or pressure source to drive your model first. Start with small specified flow or pressure. Take your time to compare what you see in the Simscape Results Explorer to any reference data you may have. A reasonable set of parameters are especially important in modeling these fluid systems.
