Troubleshooting
Something broke? I've seen every failure mode. Auth errors, timeouts, missing tools — all covered here.
Something's not working. It happens. I've catalogued every failure mode I've encountered (and the ones users have reported) so you can fix it without filing an issue. Most problems are one of three things: connection, authentication, or timeouts.
Quick Diagnosis
Before you do anything else, run this in your terminal:
curl -u "username:application_password" https://your-store.com/wp-json/fluent-cart/v2/app/initReplace username and application_password with your actual values. What you get back tells you exactly where the problem is:
| Response | What It Means |
|---|---|
| JSON with store data | Connection and auth work fine. Your issue is in the AI client config. |
401 Unauthorized | Wrong username or Application Password. |
403 Forbidden | Your user doesn't have admin permissions. |
404 Not Found | FluentCart isn't installed, or the URL is wrong. |
| Connection refused | WordPress is unreachable. Network issue, not mine. |
Common Issues
What you see: Claude Desktop has no hammer icon. Cursor shows a red dot. The AI says it can't find any FluentCart tools.
What's actually wrong (in order of likelihood):
-
Node.js missing or too old
node --versionThe MCP server needs
v22.0.0or higher. If you don't have Node at all, get it from nodejs.org. If you have an older version, upgrade. I won't apologise for requiring modern JavaScript. -
npx not found It comes with Node.js. If
which npxreturns nothing, your Node installation is broken. Reinstall. -
JSON syntax error The number one cause of "it just doesn't work." A trailing comma, a missing quote, a rogue bracket. Paste your config into jsonlint.com and see what it says. I can't debug your JSON for you.
-
Wrong config file location
- Claude Desktop (macOS):
~/Library/Application Support/Claude/claude_desktop_config.json - Claude Desktop (Windows):
%APPDATA%\Claude\claude_desktop_config.json - Cursor: Check Settings → MCP for the path
- Claude Desktop (macOS):
-
Didn't restart the app Claude Desktop, Cursor, and VS Code don't hot-reload MCP configs. Close the app completely (not just the window — quit it) and reopen.
What you see: Errors about "authentication failed", "invalid credentials", or HTTP 401.
What's actually wrong:
-
Wrong Application Password The password has spaces between groups:
aBcD eFgH iJkL mNoP. Include the spaces. It's case-sensitive. Copy it exactly. -
Wrong username Use the WordPress login name, not the display name. If your display name is "John Smith" but your login is "john", use
john. Check Users → Profile in WordPress admin. -
Application Passwords disabled Security plugins love disabling things. Wordfence, iThemes Security, Solid Security — any of them might have turned off Application Passwords. Check your security plugin settings.
Some managed hosts (WP Engine, Kinsta, etc.) also disable them by default. Check with your host.
-
HTTP instead of HTTPS WordPress blocks Application Passwords over plain HTTP. If you're on a local dev site, add this to
wp-config.php:define('WP_ENVIRONMENT_TYPE', 'local'); -
Password was deleted or regenerated If you made a new Application Password in WordPress, update it in your MCP config and restart the client. The old one is dead.
What you see: "permission denied", "forbidden", HTTP 403.
What's wrong: Your WordPress user isn't an Administrator.
Fix: Go to Users in WordPress admin and check the role. FluentCart's REST API needs admin capabilities for nearly everything. Using an Editor or Subscriber account won't work. I can't lower the permission requirements — that's FluentCart's decision, not mine.
What you see: "not found", "route not found", HTTP 404.
What's actually wrong:
-
FluentCart not installed Check Plugins in WordPress admin. FluentCart must be installed and activated. The MCP server talks to FluentCart endpoints — if FluentCart isn't there, those endpoints don't exist.
-
Wrong URL The URL should be the root of your WordPress site:
- Correct:
https://shop.example.com - Wrong:
https://shop.example.com/wp-admin/ - Wrong:
https://shop.example.com/wp-json/ - Wrong:
https://shop.example.com/(trailing slash is technically fine, I strip it)
- Correct:
-
Permalinks set to "Plain" WordPress REST API needs pretty permalinks. Go to Settings → Permalinks and pick literally anything except "Plain". Hit Save even if you don't change anything — this flushes rewrite rules.
-
REST API blocked Security plugins and
.htaccessrules sometimes block/wp-json/. Check your security plugin settings and server config.
What you see: Requests die after 30 seconds. "timeout", "aborted", "ETIMEDOUT".
What to do:
-
Increase the timeout My default is 30 seconds. If your server is slow, bump it up via the
FLUENTCART_TIMEOUTenv var (milliseconds):"env": { "FLUENTCART_URL": "https://your-store.com", "FLUENTCART_USERNAME": "admin", "FLUENTCART_APP_PASSWORD": "...", "FLUENTCART_TIMEOUT": "60000" } -
Check your server Run
curl https://your-store.com/wp-json/. If curl also hangs, that's a network or server problem. Not something the MCP server can fix. -
Ask for less data Listing 10,000 orders in one request will be slow on any server. Use pagination — "Show me the last 10 orders" instead of "Show me all orders." I designed every list tool to support
per_pageandpageparameters for exactly this reason.
What you see: The AI doesn't mention FluentCart. It says it can't access your store. It just... doesn't use the tools.
What's happening:
-
Server not connected Verify the connection:
- Claude Desktop: Settings → Developer — is
fluentcartgreen? - Cursor: Settings → MCP — green dot = connected
- Claude Code:
claude mcp list
- Claude Desktop: Settings → Developer — is
-
Too many MCP servers Some clients choke when you have 15 MCP servers connected. Try disabling the ones you're not using right now.
-
Wrong mode
- VS Code Copilot: You must be in Agent mode. Regular Chat won't use MCP tools. That's Microsoft's restriction, not mine.
- Some clients have "tool use" toggles — make sure it's on.
-
The AI just needs a nudge Sometimes the AI doesn't realise it has FluentCart tools until you mention them explicitly: "Use the FluentCart tools to show me my recent orders." After the first use, it remembers.
What you see: UNABLE_TO_VERIFY_LEAF_SIGNATURE, certificate chain errors, SSL handshake failures.
What to do:
-
Self-signed certs (local dev) If your local WordPress has a self-signed cert, add this env var:
"env": { "NODE_TLS_REJECT_UNAUTHORIZED": "0" }Local Development Only
Do not use this in production. It disables all SSL verification. You know this, but I'm contractually obligated to say it.
-
Cloudflare issues If you're behind Cloudflare with "Full (strict)" SSL, your origin server needs a valid cert. "Full" (without strict) is more forgiving.
What you see: A $49.99 product shows as 4999. Totals are 100x too large.
That's correct. FluentCart stores money in the smallest currency unit — cents, pence, grosze. 4999 = $49.99. 10000 = €100.00. 4000 = 40.00 PLN.
The AI usually converts these for you. If it doesn't, tell it: "Show prices in dollars, not cents." I documented the currency format in every tool description so the AI knows to convert, but occasionally it shows the raw value.
Still Stuck?
If none of the above helps:
- Check GitHub Issues — someone might've hit the same problem
- Open a new issue with: error message, Node.js version, AI client name, and what you tried
- Do not include your Application Password in the issue. I don't want it, and neither does anyone else