The subdomain will not resolve to the destination i have

[cscharff]

@Laudian

This means that the content (target) of your CNAME record is a domain that does not belong to you but to a different Cloudflare account.
Your website probably has a tutorial for adding custom domains. I recommend you just follow all the steps from that.

Please help me! Error 1014: CNAME Cross-User Banned

Cloudflare imports the records from your previous DNS previder. As you no longer had a DNS provider when you added the domain again, there were also no records to import. This means that the content (target) of your CNAME record is a domain that does not belong to you but to a different Cloudflare account. Your website probably has a tutorial for adding custom domains. I recommend you just follow all the steps from that.