Cloudflare is not compatible with Uscreen sites. Cloudflare uses their own caching system which doesn't combine well with our CDNs like Fastly, StackPath & Akamai.
You'll want to transfer your domain to another registrar to use with Uscreen without issues.
Important: You can however use subdomains on Cloudflare only if you choose the option DNS only in the Proxy status field:
To create a subdomain, in the DNS tab, you add a CNAME record with the name of the subdomain, pointing to your dns.uscreen.io.