Issue with the "Custom domains" doc

[cherishh]

I found an issue with this document.

Title: Custom domains
Location: https://fly.io/docs/networking/custom-domain/
Source: https://github.com/superfly/docs/blob/main/networking/custom-domain.html.markerb

Describe the issue

Under 'Custom domain - I use Cloudflare, and there seems to be a problem issuing or validating my Fly.io TLS certificate' the doc recommended user should DISABLE Universal SSL for _acme_challenge reasons. But this is not right. user should ENABLE Universal SSL or they would experiencing issue when navigate to custom domain, the browser would say ERR_SSL_VERSION_OR_CIPHER_MISMATCH.

Addtional info