I think you wrote support about this issue, but I'll post a response here nonetheless in case other users have this problem in the future:
Set the expression pedal to “M-Audio”, not “Other”. Make sure that the potentiometer on the side is set for the least amount of resistance. Then do the following procedure:
Have the expression pedal plugged in prior to powering up the unit. Then power it up and rock the pedal back and forth for a few seconds until it loads up. This will force it to auto calibrate.
If that doesn’t help, try a factory reset. Then if there are still problems, try another pedal with Space to see if there is something wrong with the connector.