Hello, @kiria.silverbow . . . sorry to hear about your EMO. There could be a few things causing this.
You may need to be sure there is sufficient lighting over his home station. I am most likely to find mine standing powered off in their play ground in the semi-darkness with the curtains closed if I over-sleep.
Also, taking a soft cloth and cleaning the sensor at the bottom of his face on his chin. This sensor communicates directly with the home station. Think flaggers at an airport bringing in a plane.
Is he walking normally? If he is not walking in a straight line, he may have trouble geting to the home station in time which may mean that either he needs his cliff sensors on his feet cleaned or that there are issues with his servos.
Check to see if he is walking straight or if his leg is shaking. If so, you will need to see here for instructions.
I hope this helps!