nextcloud/all-in-one · error · \Exception

"{domain}" is already taken. Please choose a different subdo

Error message

"{domain}" is already taken. Please choose a different subdomain and try again.

What it means

POST /domains/ returned 400 or 409 for a user-chosen slug, and the follow-up GET /domains/{name}/ returned 404, proving the account does not already own it. The dedyn.io subdomain is registered to someone else (409 collision) or the name failed validation (400).

Source

Thrown at php/src/Desec/DesecManager.php:320

            if ($code === 201) {
                return $domain;
            }

            // For a user-specified slug, the name may be unavailable (400/409) or the account's
            // domain limit may be reached (403) precisely because the user already owns this
            // domain. Reuse it rather than failing.
            if (!$random && ($code === 400 || $code === 403 || $code === 409)) {
                if ($this->ownsDomain($token, $domain)) {
                    return $domain;
                }
                if ($code === 403) {
                    throw new \Exception(
                        'Your deSEC account has reached its domain limit and "' . $domain . '" is not '
                        . 'one of your existing domains. Remove an unused domain at desec.io, or contact '
                        . 'deSEC support to raise the limit, then try again.'
                    );
                }
                throw new \Exception('"' . $domain . '" is already taken. Please choose a different subdomain and try again.');
            }

            if ($code === 409) {
                // Random slug collided with an existing name — try another.
                continue;
            }

            throw new \Exception('Unexpected response from deSEC during domain registration (HTTP ' . $code . '): ' . $res->getBody()->getContents());
        }

        throw new \Exception('Could not register a free dedyn.io domain after ' . self::MAX_SLUG_ATTEMPTS . ' attempts. Please try again.');
    }

    /**
     * Checks whether the authenticated account already owns the given domain.
     *
     * Used to recover from a failed creation when the user is reusing a slug they
     * registered earlier: GET /domains/{name}/ returns 200 only for a domain the

View on GitHub (pinned to 6b788eec5e)

Solutions

  1. Choose a different, more unique subdomain
  2. Check slug syntax: lowercase letters, digits, hyphens, must start and end alphanumerically
  3. If you believe you own it, confirm you authenticated with the same deSEC account that registered it — ownership is per-account
Defensive patterns

Strategy: try-catch

Validate before calling

// Cheap pre-check: if the account already owns the slug, creation will self-heal;
// validate slug syntax client-side to avoid the 400 variant
if (!preg_match('/^[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?$/', $slug)) {
    throw new \InvalidArgumentException('Slug must be lowercase letters, digits, hyphens; no leading/trailing hyphen.');
}

Try / catch

try {
    $domain = $manager->registerDomain($token, $slug);
} catch (\Exception $e) {
    if (str_contains($e->getMessage(), 'is already taken')) {
        showFieldError('slug', 'That subdomain is taken — pick another or leave blank for a random one');
        return;
    }
    throw $e;
}

Prevention

When it happens

Trigger: Another deSEC user already registered <slug>.dedyn.io; the slug violates the naming rules so deSEC rejects it with 400 and it is not owned by this account.

Common situations: Short popular slugs like 'cloud' or 'nextcloud' are long taken; user types an invalid name; user previously registered the slug under a different deSEC account.

Related errors

AI-assisted analysis of nextcloud/all-in-one@6b788eec5e (2026-08-21). Data as JSON: /api/errors/31dae9ca5bd1f76c. Report an issue: GitHub.