How to register a link for Viber?

Question

Viber

How is the link to the viber number written correctly so that the user clicks on the link and the call goes?
Tried like this
<a href="viber:[phone]"></a>
But it doesn't want to work like that.
I also tried this:
<a href="viber://tel:[phone]"></a>
But the same result

Answer 1

I suspect not.
viber problems with api