Problem(s) Encountered:

At some point in the night the MIS GUI stopped moving the guide probe to the correct X and Y coordinates, most likely around 1:39 am (I had a lot of issue finding the guide star/given that the probe isn't moving probably means that guidestar that the telescope was tracking was wrong). A theory is that I hit the limits of the guide probe (not the telescope, it didn't pass 1.2 airmasses and it was easy to stow back). I tried resetting the MIS GUI, by quitting the GUI and switching off the controller in the control room. But the problem didn't go away when I restarted it. I also tried to send the guide probe to the origin but it won't move past Probe X 1448 and Probe Y 7806. I get a warning  WARNING: Not at Y CCW Limit.  Also typing X = 0 and Y = 0 doesn't move the probe to beyond Probe X 1448 and Probe Y 7806. Seems like there was a similar issue July 29, 2019 and the conclusion was that it could be the sensor? Not sure. 

Solution:

Weird.  Problem was verified this morning.  I checked the guide probe positioning and it appeared to be where it claimed to be, but no command would get it to move.  I shut down the xmis2 GUI, power-cycled the MIS, and all started to work again at that point.  I’ve moved it around a bit without issue.