How do I turn the Cloudflare IPv6 gateway off with an API call

I cannot set Let’s Encrypt because of theIPv6 gateway as I was informed by my hosting provider.
However, there is no toggle anymore and I don’t know how to make an API call.
Please help

You need to have cURL or any other tool which allows you to send custom HTTP requests and then simply follow the example posted at https://api.cloudflare.com/#zone-settings-change-ipv6-setting

Though I’d be surprised if LE did not support IPv6, furthermore they seem to have announced support for it three years ago -> https://letsencrypt.org/2016/07/26/full-ipv6-support.html