I think I know why you are getting rejected although to be honest asking girls out on instagram or online is high risk for any guy so you should discount five of the seven rejections. It's the way you are approaching girls which sounds completely wrong. First of all, chatting to girls you don't know that well online is really a terrible way of getting to them romantically. Although some will chat with you online, a lot of them won't be comfortable meeting up with you romantically as they will feel scared. It also comes across a bit creepy to be honest. Second of all, you sound as though you are unrelaxed around girls. This is quite simply the worst way to be around girls as it creeps them out and comes over unconfident. If you want my advice you should put your phone down and go to places where girls are and you can talk to them in person. And when you meet them you should start by just hanging out with them as you would with your guy friends, just being completely normal with them, not throwing yourself at them, just hanging out and chilling with them and not expecting anything off of them. If there are good vibes coming off a girl you could then ask her out in person and not online. But that might take time as it takes time to get to know girls generally as they are mostly shy at first or have busy lives.