As a review of normal steps, you should initially plug the probe into the unit before turning on. The screen should say OFF across from the Time location. To set Probe, you press and hold the Probe setting on the left till the unit beeps. Then use the up/down buttons to adjust. Do the same for Temp setting and then enter Start. You should see a current degree on top with COOK to the side and current probe temp with PROBE to the side on the bottom. If you briefly push the Temp or Probe buttons, you should see your settings for those.
I did have some erratic behavior on my AQ initially dealing with the Probe. I called Cookshack and was walked through a troubleshooting process that involved taking the back cover off. We detected a wire touching the back of the plug in connector. Moving it away cured my problem. I have had a couple instances where the lettering on the screen was only partially visible. This has been very intermittent and not noticed for some time. The unit still workded as set. This screen issue also did not stay on for the whole cook. Since it has not been happening for awhile, I have not called on it.
If something is not working per the manual, call Cookshack during business hours. I was routed to Service, and believe I spoke with Tony. He was very helpful and patient. They'll take care of you.
Good luck,
Will