MAINT REQD Light on 800m after resetting it
 

As the title says. I replaced the oil and reset the light to go off. I'm 820m In and the light came on again and it's solid. What could it be?
Can't be oil since I changed it not long ago. Have tried Googling this to no avail.

Thanks for any help.

Did you reset the oil change light correctly?

Turn the key to the on position.
Determine that the odometer reading is displayed. ...
Turn the key back off.
Push and hold the reset button for the trip meters. ...
While continuing to depress the reset button, turn the key back to the "on" position, but not so far as the "start" position.

I guess I try resetting the light again following your instructions and see if it comes back on. It's just weird that the light came on after 800 or so miles of driving.