Error 1104 is a Cloudflare account-level error that appears when trying to register or add an email address that is already associated with another Cloudflare account, or a variation of it (e.g., with dots or plus signs in Gmail-style addresses). This is not a website error that visitors see — it occurs during Cloudflare account management. Cloudflare treats email variations as the same address to prevent duplicate accounts.
The exact email address or a variation of it (like [email protected] vs [email protected]) is already associated with an existing Cloudflare account.
An email with plus addressing ([email protected]) is treated as the same base email ([email protected]) that already has an account.
A previous Cloudflare account using this email was closed but the email reservation was not fully released.
Use the email address to log into Cloudflare. If an account exists, use password reset to recover access.
If you cannot recover the existing account, register with a different email address.
If you believe the email should not be registered or you need to reclaim it, contact Cloudflare support with proof of ownership.