Common error codes Cowork can return when something goes wrong, with the fix for each.
blocked-by-allowlist
Your WordPress domain isn’t on the Cowork allowlist, or Claude Desktop wasn’t restarted after you added it. See Add your domain to the Cowork allowlist.
HTTP 401 Unauthorized
Either your license key is wrong/expired, or your Application Password is wrong/revoked. Re-run /wp-setup with a fresh Application Password. If the license itself is the issue, check My Account → License Keys.
HTTP 403 Forbidden
A security plugin or host firewall blocked the request. See the security plugin compatibility articles in this category — start with Wordfence and Cloudflare WAF.
HTTP 404 / rest_no_route
The REST API isn’t reachable. See REST API not available / 404 on /wp-json.
HTTP 409 device_limit_reached
You’ve claimed your 2 device slots and tried to pair a third. Go to /my-account/devices/ and remove an old slot, then re-run /wp-setup.
HTTP 429 Too Many Requests
Cloudflare, Sucuri, or a host firewall is rate-limiting you. See Cloudflare WAF compatibility or contact your host’s support.
HTTP 500 Internal Server Error
Server-side error in WordPress. Ask Claude: “Show me my PHP error log for the last 10 minutes.” Most often a plugin or theme PHP fatal. See Common WordPress site issues.
HTTP 502 / 504 Gateway errors
Your host’s reverse proxy can’t reach PHP. Restart PHP-FPM (managed hosts have a button; self-hosted: sudo systemctl restart php8.3-fpm). If it persists, your host has an outage — check their status page.
missing_openai_api_key
Internal to MXchat support chat on wpfc.com, not a customer-side error. If you see this, contact support.
license_not_found
The license key you entered doesn’t exist in our system. Double-check it against My Account → License Keys. Watch for confusion between the letter O and the digit 0 (license keys are all uppercase letters and digits, no lowercase).
rate_limited
Soft rate limit — slow down. Cowork’s heartbeat noticed too many distinct subnets heartbeating with this license in 24h. Email support if you’re the only person using the license; we can investigate.