# Troubleshooting Firehose endpoint reachability
<a name="endpoint-troubleshooting"></a>

If the Firehose API encounters a timeout, perform the following steps to test endpoint reachability:
+ Check if API requests are made from a host in a VPC. All traffic from a VPC requires setting up a Firehose VPC endpoint. For more information, see [Using Firehose with Amazon PrivateLink](https://docs.amazonaws.cn/firehose/latest/dev/vpc.html).
+ If traffic is coming from a public network or VPC with the Firehose VPC endpoint set up in a particular subnet, run the following commands from the host to check network connectivity. The Firehose endpoint can be found at [Firehose endpoints and quotas](https://docs.amazonaws.cn/general/latest/gr/fh.html).
  + Use tools like **traceroute** or **tcping** to check if the network setup is correct. If that fails, check your network setting:

    For example:

    ```
    traceroute firehose.us-east-2.amazonaws.com
    ```

    or

    ```
    tcping firehose.us-east-2.amazonaws.com 443
    ```
  + If it appears the network setting is correct and the following command fails, check whether the [Amazon CA (Certficate Authority)](https://docs.amazonaws.cn/acm/latest/userguide/acm-overview.html) is in the trust chain. 

    For example:

    ```
    curl firehose.us-east-2.amazonaws.com 
    ```

  If the above commands succeed, try the API again to see if there is a response returned from the API.