BBoy basically gave you the lowdown on your issue. Figure out which one of these it is, and solve the root problem. Might not be a quick fix, but as long as you're aware of the cause, you can work on fixing it.
I used to tease the **** out of girls, but it didn't work because it discourages emotional connections. You're doing way too much push, and not enough pull. The better looking you are, the more valuable, charming, attractive you are in her eyes, the more you need to pull. If you push, it just creates distance.
It's easier to push (eg. tease, make fun of, break rapport, etc) because it's easier to hide behind a pretense of being disinterested. It takes more emotional strength and security to pull someone in (ie. complimenting a woman sincerely, showing your interest with no subterfuge or apologies) and doing it in a way that is smooth and natural to her.
It's more effective to pull more often than to push her away. You want her to feel connected to you, not emotionally distant. It's probably difficult for you to express yourself honestly without any pretenses or jokes or teasing. That's because it requires vulnerability. You don't have to be vulnerable when you're teasing a girl. It takes vulnerability to signal your interest, especially verbally.