James was able to answer: if the controller is showing AX/AY/AZ instead of 1X/1Y/1Z, it’s in “absolute coordinate” mode, and you can’t set a work origin.
Hit Menu + High/Low to switch back to whatever the normal mode is.
Had same error this morning trying to XY-0. Holding Menu and 1 took me back to work state. Either someone left it in another state or someone inadvertently hit some wrong buttons before me.
Unfortunately, on the handheld controller, once I hit Menu | 1 it gives no acknowledgment that anything changed, but it XY-0 properly afterwards.