# Connection troubleshooting

> What to do when you can't reach the YesCaptcha API. Failed to establish a new connection, DNS failures, proxy software interference, and SSL errors (Certificate has expired, SSLEOFError).

Source: https://docs.yescaptcha.com/en/help/troubleshooting/ · Last verified: 2026-10-15

Connection errors when calling the API (such as `Failed to establish a new connection`, `getaddrinfo failed`, timeouts or SSL errors) usually come from your machine’s network, DNS or proxy software. Work through these steps in order.

## 1\. Try the other endpoint

YesCaptcha has two endpoints: `https://api.yescaptcha.com` (global) and `https://cn.yescaptcha.com` (China). Use the China endpoint on servers in mainland China and the global one elsewhere. If you switch, query results on the same endpoint too.

```bash
curl -s https://api.yescaptcha.com/getBalance -H 'Content-Type: application/json' -d '{"clientKey": "YOUR_CLIENT_KEY"}'
curl -s https://cn.yescaptcha.com/getBalance -H 'Content-Type: application/json' -d '{"clientKey": "YOUR_CLIENT_KEY"}'
```

If either returns JSON, your network works and the problem is the route to the other endpoint.

## 2\. Check proxy software

You don’t need a proxy to reach YesCaptcha. If proxy or VPN software is running:

-   Turn it off and try again;
-   If you must keep it on, use rule-based (PAC) mode instead of global mode, or add `api.yescaptcha.com` and `cn.yescaptcha.com` to the direct list;
-   `SSLEOFError(8, 'EOF occurred in violation of protocol')` in Python with a proxy running is usually caused by the proxy too; turn it off or let these domains connect directly.

## 3\. Check the network and DNS

```bash
ping api.yescaptcha.com
```

-   “Unknown host”: DNS resolution failed. Flush the DNS cache (Windows: `ipconfig /flushdns`; macOS: `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder`), or switch your DNS to a public resolver (such as `8.8.8.8`, `223.5.5.5` or `119.29.29.29`) and try again.
-   Ping fails but the name resolves: the network may block ICMP, which doesn’t mean the API is unreachable. Trust the curl result from step 1.

## 4\. SSL certificate errors

-   `Certificate has expired` or `certificate verify failed`: first check that your **system clock** is correct, then update your OS, Python’s `certifi`, Postman or other tools so they have current root certificates.
-   Always use `https://`. Don’t switch to `http://` or turn off certificate checks to get around errors.

## 5\. Still stuck?

[Contact support](https://docs.yescaptcha.com/en/help/contact/) with the full error message, the endpoint you use, where your server is, and the curl output from step 1.