Start with the basics. Shifter in Neutral. Check the Neutral Safety Switch if one is on the bike. Precharge the battery to have good power before starting. Battery Terminals clean and snug. When something like this happens it was either something coming up to be fixed OR work done and just got overlooked by accidently.
Clutch Cable may be still in need of Adjusting and could be slightly dragging, the Starter just enough to keep it from starting. Please be sitting on the bike so if a jolt or starter catches it wont pull forward causing problems. A pit Stand comes in handy for getting rear of bike up to check this type of problem when working along. Recheck your work it may be a small adjustment .Jimi*