Hi @liblab ! Welcome to the community 🥳
I've tested the Whatsapp button and it seems to link to the correct page. Is the phone number correct and in the correct format as Whatsapp suggests?
Omit any zeroes, brackets or dashes when adding the phone number in international format.
As you said, it works for Android & desktop (just tested it), personally I do not own an iPhone.
I do see that they've changed the url suggestion from 'api.whatsapp.com' to 'wa.me' in the documentation, so that's something for us to look at, but shouldn't be the problem as it redirects to the same page.