ᐅ Removing a drawer from an older Ikea kitchen cabinet

Hello,
my drawer under the oven is driving me crazy:
I recently noticed that it is completely crooked in the drawer slide. I wanted to unhook it once and then put it back properly. However, on one side I just can’t get the drawer out of the rail.
My kitchen is from 2007. On the drawer slide it says "blum Tandembox Plus". At the front, underneath, there is a small gray lever that apparently allows you to unlock the drawer; using that, the drawer did release, but it seems to be stuck somewhere in the middle or at the back.
I have already searched everything possible online but can’t get any further. According to the internet, you should be able to simply lift it, but when I try that, nothing moves.
Maybe someone here has advice??? I would be very grateful.

Lift, pull, lower slightly, pull. If it gets stuck, just pull a bit harder.

Thanks for the quick reply, but that wasn’t it either.

Apparently, the rail has become misaligned somewhere it shouldn’t be...

I’m afraid it won’t be resolved by the standard approach anymore.

Pull harder.