While working with a virtual or dedicated server, errors may periodically occur. Don’t be afraid or panic – there is a solution! But first, let’s look at the definition of this 504 error. The most common causes of this error is considered to be one of the most common problems faced by website owners and users. This error indicates that the server acting as a gateway or proxy did not receive a timely response from the upstream server. This may result in the page not loading, which leads to user dissatisfaction and potential business losses. In this article we will look at the main causes of this error and possible ways to eliminate it.

Causes for Error 504

The AvaHost team will try to describe the most common problems and causes of this error. Here are some of them:

Problems with the destination server

The most obvious cause of a 504 error is that the server being contacted by the proxy or gateway does not respond within the specified time. This may be caused by:

• Server overload. The server cannot cope with the number of requests and cannot process them in a timely manner.
• Server crash. The server may be temporarily unavailable due to technical work, accidents or equipment failures.
• Configuration problems. Incorrect server settings can lead to delays in request processing.

Network problems

Network level errors can also cause a 504 Gateway Timeout:

• Routing problems. Bad routes or overloaded routers can delay or block traffic.
• Network failures. Problems with Internet service providers or DDoS attacks can slow down or block network traffic.

DNS problems

The Domain Name System (DNS) is responsible for resolving domain names into IP addresses. If there are problems with DNS, this may result in a 504 error:

• Invalid DNS records. Incorrect or outdated DNS records may result in an inability to establish a connection to the destination server.
• Problems with DNS servers. If DNS servers are not working properly, it can make domain name resolution difficult or impossible.

Problems with intermediate servers

Intermediate servers such as proxy servers or cache servers can also cause the 504 error:

• Proxy server overload. If the proxy server can’t keep up with the number of requests, it can cause delays.
• Incorrect proxy server configuration. Incorrect settings may prevent normal operation.

Possible Solutions for Error 504

Some ways to solve the problem of 502 error occurring on your server.

Reboot the server

No matter how trivial it may sound, the first thing worth trying is rebooting the server. Temporary failures or overloads can be resolved by simply restarting the following services:

• Rebooting the web server. Apache, Nginx or any other web server.
• Reloading the database. MySQL, PostgreSQL or other database management system.

Optimizing server performance

To avoid server overload, you need to optimize its performance:

• Server scaling. Increasing the number of servers to distribute the load.
• Code optimization. Improving web application code to use resources more efficiently.
• Using cachingю Implement caching at the web server and database levels.

Check and correct DNS settings

DNS issues can be resolved by:

• Updating DNS Records. Make sure your DNS records are up to date and correct.
• Using reliable DNS servers. Switch to more reliable and faster DNS services.

Checking network settings

Network problems can be identified and corrected:

• Route testing. Using tools to test routes and find problem nodes.
• QoS Configuration. Сonfigure quality of service (QoS) to prioritize important traffic.

Optimizing the operation of intermediate servers

If the problem is with proxy or cache servers:

• Proxy Server Setup. Make sure the proxy server is configured correctly and distributes the load effectively.
• Clear cache. Clear your cache regularly to prevent it from becoming full and slowing down.