Fix · Domains and DNS

My subdomain (shop.example.com) does not work

Not checked against the vendor's current screens

What you may see

I created a subdomain and it shows an error

Most likely cause

The subdomain needs its own record in DNS and a matching setting at the host that serves it.

Check first (about two minutes)

Look up the subdomain with a public tool: NXDOMAIN means no record.

The fix prompt

What you type here never leaves your browser. The search runs on this page, and nothing is sent to a server or to an AI.

The exact error or what you see

What you did before it happened

Kept only in this browser, on this device. Keys and passwords are removed before anything is saved.

Prompt language

You are a patient senior engineer who knows domain names and DNS settings and explains them to people who are not developers. I am not a developer, so explain every step in plain words and tell me exactly which button, menu or command you mean. If you are not sure about something, say so; do not guess.

Menu and button names change over time. If you cannot find a button or page I mention, say so and tell me what to look for instead of guessing.

THE PROBLEM
My subdomain (shop.example.com) does not work

THE EXACT ERROR OR WHAT I SEE
[paste the exact error here]

WHAT I DID BEFORE IT HAPPENED
[write in a few words what you did before it happened]

MOST LIKELY CAUSE
The subdomain needs its own record in DNS and a matching setting at the host that serves it.

DO THESE STEPS, IN THIS ORDER
1. Check the record (type and name, where "shop" is the name, not the full domain at many registrars) and the host's domain list.
2. Add the subdomain to the host project, then add the record it asks for.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- The subdomain opens over https.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not create a wildcard record unless needed.
- Anything I did not ask about: the design, the text, other pages, other settings or the data.
- Do not delete files, data or branches, do not reset or force-push, and do not rewrite history, unless you first show me exactly what would be lost and I say yes.
- Do not paste, print or ask me to paste a password or secret key into this chat. If one is needed, tell me which settings page of the right service to store it in.

WHEN YOU FINISH
Explain in simple words what you changed (file by file or setting by setting), why you changed it, and how I can undo it.

Paste it into Claude, ChatGPT, Gemini or Cursor, then follow what it says.

After you tried it, did it work?

Steps

Check the record (type and name, where "shop" is the name, not the full domain at many registrars) and the host's domain list.
Add the subdomain to the host project, then add the record it asks for.

Do not do this

Do not point many subdomains at one app without a plan.
Do not create a wildcard record unless needed.

Try another entry