This may be an obvious question, but are you sure you are in Performance mode rather than Patch mode? And are you sure all the reception (Rx) channels in Performance mode are turned on?

If you *are* in Performance mode, and if all the receive channels *are* on, and it still doesn't work, then maybe you could describe your setup a bit more closely, e.g., what keyboards are transmitting on what channels to the XP80 and which performance parts you're trying to address and which channels they are set to.