Hips and Straddle planche.

I have problem lifting my hips while performing straddle planche, my lean is pretty good, but i feel like my lower back and the glute area are so frozen. Could you give me some exercises or tips how to extend my legs ?

Most likely your shoulders are not strong enough. The strength required in the glutes and lower back is really not very much compared to what's required in the shoulders. If you can do reverse leg-lifts, you have the back/glute strength required to hold a planche.