DIAGNOSIS You probably disconnected or damaged the 120V power cord during the stove swap. This model plugs into a dedicated outlet inside the cabinet above.
FIX Pull the microwave forward slightly from the cabinet (have a helper support it). Check the power plug is fully seated in the outlet. Verify the circuit breaker or GFCI that feeds that outlet hasn't tripped.
IF THAT DIDN'T WORK The plug or cord may have been pinched and shorted. You'll need to pull the unit down to inspect the cord for damage. A damaged cord requires a service call to replace.
HEADS UP The unit is heavy. Do not attempt to fully remove it alone. The power cord is not user-serviceable without disassembly.