> For the complete documentation index, see [llms.txt](https://docs.link11.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.link11.com/using-link11/how-do-i.../diagnose-origin-errors.md).

# Diagnose origin errors

## Introduction <a href="#id-webddos-originerror-introduction" id="id-webddos-originerror-introduction"></a>

Link11 makes every effort to ensure that connections destined for your applications are made without issue. While we do our best to limit disruptions to legitimate traffic crossing our network, Link11 is unable to prevent clients from encountering errors from the origin or “origin errors”.

An origin error occurs when someone, like a website visitor using a browser, tries to access your site but encounters a problem reaching the server where your website is hosted. These disruptions can make your site temporarily unreachable, potentially impacting your business operations and revenue.

## TCP-Based Errors <a href="#id-webddos-originerror-tcp-basederrors" id="id-webddos-originerror-tcp-basederrors"></a>

When it comes to TCP-related origin errors, there are three main categories:

1. **Connection Refused**: This error indicates that a particular port on the origin server is closed. It can happen for various reasons, such as when the web server or load balancer is not functioning correctly, even if the server itself is online. Please check that the required ports are open and that inbound communication into the network is not being filtered or blocked.
2. **Connection Timeout**: The second type of origin error occurs when the origin server doesn't respond to a request within a set timeframe, typically around 30 seconds. This can happen due to server crashes, high server loads, or ongoing maintenance activities. Connection timeouts can be increased on the origin side, and WebGUI offers the ability to [increase the time Link11 will wait for a response](/product-guides/web-ddos/interface/instances/http-settings.md#origin-timeouts).
3. **Connection Reset By Peer**: This error occurs when a connection with the origin server is initially successful but is abruptly terminated by the server itself or a load balancer without following standard closure protocols. Diagnosing this error can be complex, as it could be caused by factors like overloaded server resources, network issues, security threats, or configuration problems on the origin server.

## SSL-Based Errors <a href="#id-webddos-originerror-ssl-basederrors" id="id-webddos-originerror-ssl-basederrors"></a>

Maintaining web accessibility is not only about keeping a continuous connection but also about securely transmitting data. In addition to TCP-based errors, SSL-based issues are equally critical, as they relate to the secure communication layer between clients and servers. Here are three common SSL-related issues that can affect communication with the origin server:

1. **Configuration Error**: This error occurs when the origin server fails to communicate using the correct TLS protocol. Such issues often arise from misconfigurations of supported protocols and/or ciphers.
2. **Certificate Problem**: This problem arises when the certificate on the origin server has expired, is invalid, or is considered untrustworthy by our system. This is especially common with self-signed certificates.
3. **Encryption Problem**: Encryption is crucial for data privacy during transmission. Problems can occur when there's a breakdown in the encrypted connection between a client and the origin server. Various factors, such as network congestion, high latency, or software glitches on the origin server, can trigger this issue.

We hope this information helps you understand and address potential origin errors effectively, ensuring the continuous and secure operation of your website.