Is there just one Dosatron pump that supplies soap for both the low- and high-pressure? It could be a problem with the Dosatron or its foot valve. It would help to know more about your set-up and the manufacturer.
In the past I have had this type of pump lock in between the stroke where it switches from up to down. Unscrew the top and manually cycle the pump down and up a couple of times. Screw the top back on and it should work. You should hear a clicking sound if the pump is working properly.