Resolving a 429 or 503 Error (Web Server Related)

This guide details the errors of type Rejected, too many connections from this host if they occur while visiting a website.

Origin of the Errors

429 Too Many Requests

This error occurs when the server is overwhelmed by a large number of requests in a short period, which can be due to heavy usage of the site or abuse.

503 Service Temporarily Unavailable

This error can be caused by several factors, including scheduled maintenance work on the server, server overload due to high traffic, or the execution of a script that exceeds the server's resource limits.

Rejected, too many connections from this host

This error occurs when the server rejects connections due to a high number of simultaneous connections from the same IP address. Check "Access and Error Logs" on your hosting dashboard to find multiple entries like:

[Fri Sep 02 11:40:31] [error] [client 222.111.123.123] Rejected, too many connections from this host. (vhost:domain.xyz uri:/js/modules/blocktopmenu/js/superfish-modified.js current:34 limit:30

[Fri Sep 02 11:40:31] [error] [client 222.111.123.123] Rejected, too many connections from this host. (vhost:domain.xyz uri:/js/modules/blocktopmenu/js/hoverIntent.js current:34 limit:30

[Fri Sep 02 11:40:31] [error] [client 222.111.123.123] Rejected, too many connections from this host. (vhost:domain.xyz uri:/js/modules/productscategory/productscategory.js current:34 limit:30

[Fri Sep 02 11:40:31] [error] [client 222.111.123.123] Rejected, too many connections from this host. (vhost:domain.xyz uri:/modules/feeder/rss.php current:35 limit:30

[Fri Sep 02 11:40:31] [error] [client 222.111.123.123] Rejected, too many connections from this host. (vhost:domain.xyz uri:/js/modules/favoriteproducts/favoriteproducts.js current:34 limit:30

In this example, the IP 222.111.123.123 is making 30 simultaneous connections on each page, therefore it is automatically rejected as this may resemble an attack or scan.

Resolution Steps

Some steps to resolve these errors:

• Check scripts that make multiple connections to the server to display data.
• Optimize the concerned script(s) so that they require fewer resources.
• Increase the limits of the concerned site to allow the script to do what it needs to do and/or limit the number of simultaneous connections (especially on a Cloud Server where limits - memory, execution time, simultaneous connections - can be significantly increased).
• Migrate your hosting to a Cloud Server.