Custom Button link Whatsapp

Hello, I’m trying to set a custom link in a custom button but it’s giving me some problems.

I could set a “mailto: xxxxx” custom link to my first custom button but now I’d like to have a second custom button with the following link:

whatsapp://00123456789

what I get instead is a “javascript.void(0);” link. You can check it at cholbiosteopathie.com

I have search for a solution and tried to uninstall and reinstall the plug-in without success.

Has anyone idea whether this is possible at all and how to achieve it?

Thanks in advance!!!

https://www.ads-software.com/plugins/ultimate-social-media-icons/