The first time this happened was about 12mths ago and I managed to cure the problem with this easy to do fix.
Firstly identify the switch below the clutch leave ( Fig1.) with the screw driver identifying the screw to be undone.
Then identify the contacts and the pressure switch (Fig2) When the pressure switch is pressed in it causes the contacts to come together thus completing a circuit. (enabling the power to allow the engine to start whilst in gear). This will only be done when the clutch lever in operated.
These contact can become soiled and needs to be cleaned. I do this with a narrow piece of wet and dry paper (pics 3) This is folded to form a doubled sided fine paper file( fig 4).
Place this in between the contacts.(Fig5).
Now press the pressure switch in.( Fig 6) this allows the contacts to come onto the paper file. Move the paper file up and down a few times and withdraw it.
Just reverse the process of putting the switch back below the handle bars and tightening the screw.
That just may have saved you a few dollars (Euros in my case).
Unfortunately I'm one of those unfortunate people now being abandoned abroad through those Brexit fools in the UK. Viva Espana ( EU)