when did you ride it last?
any problems felt when you rolled it into the garage?
mechanically
sounds like the plates are sticking, what oil have you used?
another possibility is frayed cable.
if it was ok when you last rode it, you shouldn't have the need to adjust the cable. has the cable been replaced or lubricated?
always presuming back wheel hasn't been removed or if it has , been put I out of line.
as Burbler says, electronically, there could be a couple of cut out switches, sidestand or clutch, maybe even brake. any of these could cut engine.
