Have you checked the following
Control Sticks are all the way out
Pto ( deck blades) is pushed down and off
The parking break is on
I know this is dumb but make sure your sitting in the seat.
If you have checked all of this then it might be a bad safety switch or fuse. I would just let the dealer check this out, and not risk voiding the warranty, or damaging something important. Sorry for the problems you are having, scags a great machines!
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