The bot is not targetting by itself, if you're using scripts that came with the bot, those don't really target mobs unless they are around them, meaning the range is not that long. Normally what I do is that before starting the bot, I choose a good spot with a lot of mobs around and I target the first mob, then I start the bot and then after the first target is dead he will just keep targetting the same kind of mob over and over. You can try to do that or you can always make your own script telling the bot what mob to target and when to target it, however that takes a little bit more effort. ;)