Simulation TI antenna DN024

Hello, I am new in the area of antennas, I am looking to develop an antenna for a pcb board, using the following antenna as a reference https://www.ti.com/lit/an/swra227e/swra227e.pdf?ts=1663929177207 , I am trying to simulate this antenna in matlab using the pcb antenna designer app, in order to find the correct dimension of the segment 4 (L4) of the antenna so that it can resonate at the frequency of 915Mhz, but after many attempts I can't even get close to the values mentioned in the document, I resort to your help in order to at least be able to make the antenna resonate the frequency of 868Mhz that the document mentions or at least indicate the possible error, I greatly appreciate your help.

The file of my project: https://drive.google.com/drive/folders/1yTHuEQXddYmNBtl45p17Q2cfCeT3PEnS?usp=sharing

P.D: You can also find the design of this antenna in this document http://www.ti.com/tool/TIDA-00816 implemented in a PCB.

If you need any other information let me know.