Why does www work but my domain without www doesn’t?

Two names, four places

example.com and www.example.com are different DNS names. Nothing connects them automatically. For both to work, each has to be right in four places: a DNS record for each name; each name added to the host’s project; each name covered by the certificate; and a redirect from one to the other so visitors end up in one place. One name can be complete while the other is missing at any of the four, which is why “www works but the plain domain doesn’t” (or the reverse) is so common and so easy to fix once you know which place.

Which failure do you have?

Open the failing name in a private window and note what happens:

The DNS layer: the apex and www take different records

The bare domain, called the apex and written @ in DNS panels, can’t carry an ordinary CNAME record alongside its other records; that’s a rule of DNS itself. So hosts ask for an A record at the apex, pointing at an address such as Vercel’s 76.76.21.21 or Netlify’s 75.2.60.5, or an ALIAS or flattened CNAME if your DNS provider offers one. The www name is an ordinary subdomain and takes a CNAME to the host’s name. Because the two records look different, people often set one and assume the other follows. It doesn’t.

Check both with a lookup tool: A and AAAA for the apex, CNAME for www. The DNS-change guide explains how to query the authoritative nameservers so you’re not looking at a cached answer. The name that fails will have no record, the wrong record, or an old record left over: a common one is a stale AAAA record at the apex sending phones to the old host, which Netlify’s troubleshooting page singles out because its load balancer doesn’t support IPv6, and Vercel doesn’t support IPv6 either. Netlify also warns that multiple A records at the apex cause certificate failures. Fix the record for the failing name only, and remove what shouldn’t be there.

The host layer: both names must be added to the project

DNS pointing at a host only gets the request to the host’s door. The host then needs to know which project the name belongs to. If only one name was added to the project, the other arrives at the host and gets a “domain not configured” page, a 404, or whatever default the host serves. Open the project’s domain settings and confirm both names are listed. Vercel prompts you to add www when you add the apex and vice versa; Netlify adds both automatically when you add either; Cloudflare Workers needs each custom domain added, and Pages needs each name added too. Add the missing one and give the host a minute to verify it.

The certificate layer: the name has to be on the certificate

Hosts issue certificates per name they know about, and only once that name’s DNS points at them. So a name added late, or whose DNS was fixed late, gets its certificate late. Netlify says outright that DNS has to be configured in advance for every alias it should include on the certificate. The symptom is a security warning on one name and a clean padlock on the other. Wait for the host’s domain screen to show the certificate as issued for the second name; if it stays pending, the HTTPS guide has the causes, including CAA records and Cloudflare’s proxy.

The redirect layer: redirects aren’t a substitute for DNS

Two distinct mistakes live here. First, registrars offer “domain forwarding”, which makes the apex redirect to www by pointing the apex at the registrar’s own server. It works for http, but the registrar usually can’t serve a certificate for your domain, so https://example.com fails while https://www.example.com works. The fix is to give the apex a real record at the host and let the host do the redirect.

Second, a redirect loop: the apex redirects to www and something redirects www back, or Cloudflare’s Flexible SSL mode bounces between http and https with a host that forces https. Set the redirect in one place, the host, and if Cloudflare proxies the record, use its Full (strict) mode.

How Vercel, Netlify and Cloudflare handle both names today

• Vercel asks for an A record at the apex and a per-project CNAME at www, prompts you to add the second name when you add the first, and lets you set which one redirects to the other with a “Redirect to” option. It recommends www as the primary. It doesn’t support IPv6, so there should be no AAAA record.
• Netlify asks for an ALIAS to apex-loadbalancer.netlify.com or an A record to 75.2.60.5 at the apex and a CNAME to your netlify.app address at www. Adding either name adds both, and whichever you set as primary gets the other redirected to it. With external DNS it recommends www as primary.
• Cloudflare can flatten a CNAME at the apex when it holds your DNS, so the apex can point at a name. For a Worker custom domain, Cloudflare creates the records itself, one per name you add. For Pages, www can be a CNAME from any provider but the apex has to be a zone on Cloudflare.

Pick one canonical version and redirect the other

Search engines and shared links should land on one address. Choose it once. Both names still need DNS records and both need to be on the certificate, so that whichever a visitor types, they’re redirected securely to the one you chose. If your DNS is at an outside provider, the hosts’ own advice is to make www primary, because its CNAME can follow the host’s network while the apex A record can’t. If the site has always been on the bare domain and links point there, keep it; the point is consistency, not which one.

Checklist

Sources

The rules and product behaviour described above were checked against these pages when the guide was last updated. If something here has changed, these are the places to look.

• Domain names: concepts and facilities, RFC 1034 §3.6.2 · IETF
• Adding a custom domain · Vercel
• Deploying and redirecting domains · Vercel
• Domains troubleshooting · Vercel
• Working with DNS · Vercel
• Configure external DNS for a custom domain · Netlify
• Manage multiple domains · Netlify
• HTTPS (SSL) · Netlify
• Troubleshoot SSL and HTTPS · Netlify
• CNAME flattening · Cloudflare
• Custom domains for Workers · Cloudflare
• Custom domains for Pages · Cloudflare
• Too many redirects · Cloudflare
• Encryption modes · Cloudflare