cpanel wildcard configuration help

[Crazyplayer364]

I'm trying to setup the Let's Encrypt SSL certificates on the nginx proxy manager. But say as a example I want to add

*.testdomain.com
With DNS challenge I need to add the details

DNS provider
cpanel

It asks for these details
cpanel_url = https://cpanel.example.com:2083/
cpanel_username = user
cpanel_password = password

But when I enter my details it doesn't work.

That's what I want to use the API key for instead. Hope that makes sense