Summary

This configuration error prevents Cloudflare's primary DNS setting, which is the preferred method for managing CNAME records across multiple accounts. Since Cloudflare strictly forbids configuring a custom domain directly on the CNAME, attempting to do so manually fails the security policy check. Therefore, users must switch to the official Cloudflares approach by creating a custom domain, which properly validates the CNAME against the required security settings on your R2 bucket.

Title

CNAME Cross-User Banned | Cloudflare

Description

CNAME Cross-User Banned | Cloudflare

Keywords

page, website, security, more, details, custom, domain, cookies, error, cross, user, part, network, host, accounts, policy, https

NS Lookup

A 172.67.193.91, A 104.21.73.236

Dates

Created 2026-03-07

Updated 2026-04-15

Summarized 2026-04-16