Introduction

When the www version of a site stops working while the apex domain still loads, the problem is usually not the whole website. It is usually a hostname-specific issue involving DNS, redirects, proxy setup, or certificate coverage. The safest fix is to verify that www is intentionally configured instead of assuming it should work automatically.

Symptoms

  • example.com loads but www.example.com fails or times out
  • The browser shows DNS, SSL, or redirect errors only on the www hostname
  • Cloudflare, hosting, or DNS records were changed recently
  • The site migrated to a new platform and only one hostname was updated
  • SSL checks show the certificate covers the apex domain but not www

Common Causes

  • There is no www DNS record or it points to the wrong target
  • The www CNAME still references an old platform, server, or CDN endpoint
  • Redirect rules send www to a hostname that is not configured correctly
  • The TLS certificate does not include the www hostname
  • The CDN or hosting platform expects both hostnames to be added explicitly

Step-by-Step Fix

  1. Check whether www has a valid DNS record, usually a CNAME or an A record, and confirm it points to the current live platform.
  2. Compare the www target with the apex domain target so you can see whether only one hostname was updated during migration.
  3. Verify that your CDN, reverse proxy, or hosting platform has www added as an active domain and not just the root domain.
  4. Test HTTPS on www specifically and confirm the certificate SAN list includes that hostname.
  5. Review redirect rules so www resolves cleanly to the canonical hostname instead of looping or pointing visitors to a dead destination.
  6. If the site uses Cloudflare or another proxy, confirm the www record is proxied or DNS-only intentionally and not left in the wrong mode by accident.
  7. Wait for DNS propagation only after confirming the new record is correct, because waiting does not fix a wrong target.
  8. Retest both www and non-www from an uncached browser session and an external DNS checker.
  9. Keep both hostnames documented in DNS, SSL renewal, and platform domain settings so future changes do not break one version silently.