Symptom: adding a domain in the dashboard fails with a message like "The example.com domain has been registered already".
1. Confirm the cause: this means the domain is active on a different Resend account. Common reasons: a teammate or contractor added it, or you are logged into a different account than the one that first added it.
2. First check: ask your team whether someone already uses Resend, and double-check which account you are signed into. The cheapest fix is using the account that already has it.
3. Fix via claim: on the Domains page, add the domain again and click Start claim when the in-use prompt appears. Resend gives you a DNS TXT record to add.
4. Add that TXT record at your DNS provider to prove ownership. The claim expires in 7 days, so do not let it sit.
5. If you previously started a claim, re-submit the same domain and click Continue claim to pick up where you left off.
6. Verify: once the claim completes, the domain appears in your account and you can add the normal sending records. If you cannot add DNS records, contact Resend support.