Since the battery wasn't charged I assume the bike had been setting for some time.
I would suggest disconnectng the battery and cleaning the terminals. Let it disconnected and follow the
large wire from the "+" terminal and clean and tighten all connections including the one at the starter.
Check and clean the small wire's connectors at the starter relay. It will be the thing with the two fuses.
One is a spare.
Then clean and tighten the "-" ones also.
Keep us posted.