Mine has had a similar problem several times. The small screw holding the clutch switch has become loose.
From below the clutch lever on the bars follow the wire till you locate a small micro switch. With a small posi drive remove the tiny screw and extract the switch.
With the bike on the stand wheel off the ground, bike in gear, switch hanging loose, press the starter and see what happens. Note- be quick to turn it off if it fires.
If nothing try pressing the switch until it clicks, press the starter again and see what happens. (this procedure is because I cannot remember which mode the switch needs to be in)
If again nothing the micro switch could have failed, luckily on mine it only needed repositioning in the clutch lever assembly.
When refitting the switch coat the screw in lots of grease, its not to lube it but to hold it into the housing while you position the switch, if it falls out YOU WILL lose it.