Resistor Terminal Input Voltage Range (Terminals A, B and W) Min: VSS Max:VDD
To fix it, you'll have to offset the input signals. Depending on how your amplifier is coupled, you might have to shift the output signals back to bipolar.
Yes, feed the signal thru a capacitor, to the junction of two 100K resistors between 5V and GND, so the junction sits at 2.5V going into the pot.Then feed the pot output thru a cap again to the amplifier.
C2-R6-R7 not wired correctly. Polarity of C3/C4 are not wired the same.