Common errors on Nginx

There are several common errors that can occur when using Nginx, including:

1. Configuration errors:

These occur when there is a mistake in the Nginx configuration file, such as a syntax error or an incorrect file path.

2. File permission errors: 

These occur when Nginx does not have permission to access a file or directory.

3. Connection refused: 

This error message indicates that Nginx is running, but it is not able to connect to the backend server. This can be caused by a firewall or a problem with the backend server.

4. 502 Bad Gateway: 

This error message indicates that Nginx was able to connect to the backend server, but the backend server returned an invalid response. This can be caused by a problem with the backend server or by a misconfigured Nginx proxy.

5. 404 Not Found: 

This error message indicates that Nginx is running, but the requested URL was not found on the server. This can be caused by a misconfigured Nginx server or by a problem with the backend application.

It's important to check the error logs for more information about the specific error and troubleshoot accordingly.