Vani shot 72-74 for a total of 146 and was one shot off the cut, which fell at one-over 145.
The other two Indians, Neha Tripathi (75-72) and Amandeep Drall (77-76) also exited early.
Georgia Hall fired a second round of 67 to take a one- stroke lead at the halfway stage. At 12-under-par, she is one stroke ahead of Carlota Ciganda and home-town star and defending champion Azahara Muoz, who equalled the course record with a 64, only to be followed by another 64 from Supamas Sangchan of Thailand moments later in hot and sunny conditions at Real Club de Golf Guadalmina.