Not receiving verification call

[3CTEL]

I am trying to integrate whatsapp with 3cx. so the scenario is when I try to make WA profile (as per step 1 of integration guide) I get the error that this number is not on WA business platform and use the right number. As per my knowledge we need a number that is not on WA.
if I move on to next steps and then add number on the page where it asks to select the number (8th point in step 2) I don't receive number verification call. We have integrated WA with 3cx on other 3cx PBX the same way but for some reason we can't get it done for this one. can anyone help me out ?
https://www.3cx.com/docs/manual/whatsapp/
using this guide and system is on V18.

 

[VoIPTools]

I created a video for 3CX V18 setup for Whatsapp. I do not know if there are significant changes to the setup in V20, but perhaps you will find the video helpful? If I need to do an update for V20, let me know.

 

[3CTEL]

I created a video for 3CX V18 setup for Whatsapp. I do not know if there are significant changes to the setup in V20, but perhaps you will find the video helpful? If I need to do an update for V20, let me know.

This is exactly how I am doing it , my issue is I am not receiving call or sms for code. I have checked and in inbound rules the number is routed to my user.