Error 503 or status code 503 is one of the best-known and most frequent error messages when calling up websites. The Error 503 Service unavailable can be encountered by users on desktop PCs, tablets, notebooks or smartphones. The server to which the entered URL refers reports that the desired homepage is temporarily unavailable. Depending on the browser, HTTP Server Error 503 or something similar can also be displayed as the status code, since it is formally an HTTP code that describes the server-side failure of the request.
Typical reasons for the 503 error
According to electronicsmatter, there are essentially the following possible causes for the status code 503 to be output:
- The homepage is currently being maintained and the admin has taken it offline.
- At the time in question, the server receives more connection requests than it can process. For example, this can be due to a short-term higher traffic, but also to a long-term discrepancy between the requirements of the web project and the scope of services of the server.
- In some cases malware or spam attacks (DDOS attacks) have overloaded the server.
- Incorrect programming in the web application or the content management system prevents the server from successfully displaying the homepage.
- The DNS server is poorly configured on the client computer or router.
- There is a fault in the network: Internet nodes or gateways are unstable.
- Important services on the target server have failed.
What are the SEO effects of the Error 503 Service unavailable?
First of all, an inaccessible website affects the public’s perception. Customers and interested parties with little IT affinity might think that the web shop or company website has generally been taken offline. For companies that rely on e-commerce, this can mean a migration of interested buyers to competitors. In addition to a negative user experience, an HTTP 503 problem often leads to poor search engine ranking. Finally, while the page is offline, no Google robot can index. In addition, no traffic is generated during this time and backlinks from other sites come to nothing. In summary, it can be said that 503 cases preceded the successReduce on-page optimization.
Status code 503: How to prevent
- Expand server capacities in good time: Before an expected higher number of visitors, you should rent more storage and computing power from the hosting provider or commission the company’s IT department with an expansion.
- Adapted server monitoring: The accessibility of the site can be checked automatically at short intervals. Then every case that leads to an Error 503 Service unavailable message is reported so that faults can be eliminated quickly.
- Extensive stress test before the productive operation of a new website: In this way, the resilience and limits of certain services can be determined before an HTTP error like the one with the status code 503 occurs. Administrators can therefore make preparations in good time and optimize the system.
- Redundant systems: If a fault is detected during monitoring, the system can automatically switch to a backup. This is particularly relevant when additional services such as databases or PHP interpreters are in the network.
- Update used software regularly: Outdated applications with known vulnerabilities increase the risk of malware or spam attacks, which can lead to a 503 error. Depending on the server package booked, your own IT department or that of the hosting provider must ensure that all programs involved are updated promptly.
- Finding and correcting programming errors: Incorrect programming in the web project or in the content management software, for example, leads to the output of an Error 503 message because loading times are too long. The reasons are often too many database accesses and badly programmed or too many plug-ins.
Other important website error codes
The 503 error belongs to error group 500. Status messages from this area always indicate problems with servers, internal data processing or client communication. The error code 500 is a so-called catch-all HTTP error. It only gives a very general indication of the cause and possible solutions. More specific codes, such as the Error 503 Service unavailable, facilitate the search for a solution. Other common, more specific errors from this group are HTTP Error 502 Bad Gateway and 504 Gateway Timeout. If a website cannot (no longer) be found on the server after entering a URL, the error code 404 does not appear, but the error status code 404.