Is dual power supply's ground coupled?
The spec sheet for that supply says it has two isolated outputs.  If you want to use them as two positive supplies, with the same ground, you MUST connect the two negative terminals together, and to the ground of your circuit.

Since the two supplies are isolated, they could also be used to provide positive and negative supplies (as often needed for audio amplifiers and other analog circuits) by connecting the negative terminal of one supply to the positive terminal of the other, and calling that connection "ground".