Troubleshooting 5xx Responses

Applies To:

HTTP LargeThis platform has been optimized to cache and deliver static content (e.g., HTML, CSS, JavaScript, ISO, multimedia, and software downloads, etc.) over HTTP or HTTPS.

HTTP SmallLegacy. If you are currently serving traffic over this platform, then you may continue to do so. However, we recommend that you serve your traffic over our more robust HTTP Large platform.

ADNThe Application Delivery Network platform has been optimized to deliver dynamic content (e.g., login credentials, account information, etc.) over HTTP or HTTPS. Typically, user-specific and database-driven content are served over this platform.

5xx status codes are generated by the web server associated with a customer origin configuration. By default, our edge servers will forward a 5xx response to requesterRefers to the user that requested content.s when a web server is unavailable and one of the following conditions are met:

The web server has not been configured to reject connections when it is unavailable.
- This type of setup may cause the web server to return an invalid response to our edge servers.
- This type of setup will prevent a max-stale directive from taking effect.
The requested content has not been cached on the POP closest to the requester.
The requested content has been cached on the POP closest to the requester, but the asset's Cache Control response does not contain a max-stale directive.
The requested content has been cached on the POP closest to the requester, but the asset's Cache Control response contains both max-stale and must-revalidate directives.

5xx responses are not typically related to our CDN service and must be resolved by a webmaster or system administrator.

Mitigation

Mitigate the effects of an unavailable web server by configuring it to:

Reject connections when it is unavailable.
Set an appropriate max-stale policy.
Only set a must-revalidate directive as needed.

The Origin Shield feature also helps mitigate 5xx responses by providing an additional caching layer from which a cached response may be served to requesters.

Learn more about Origin Shield (Customer Origin Group / Legacy).

Troubleshooting a Network Issue

A 5xx response may be a result of a network issue between the web server and the CDN.

Perform a traceroute from the web server experiencing issues.

Service	Description
ADN	Perform a traceroute to the primary ADN Gateway server as defined in the corresponding customer origin configuration. Learn more.
HTTP Large & HTTP Small	Perform a traceroute to the desired platform-specific domain. Learn more.
Origin Shield	If Origin Shield has been enabled on the corresponding customer origin configuration, then perform a traceroute to that Origin Shield POP. Learn more.

Service

Description

ADN

Perform a traceroute to the primary ADN Gateway server as defined in the corresponding customer origin configuration.

Learn more.

HTTP Large & HTTP Small

Perform a traceroute to the desired platform-specific domain.

Learn more.

Origin Shield

If Origin Shield has been enabled on the corresponding customer origin configuration, then perform a traceroute to that Origin Shield POP.

Learn more.

A traceroute that reveals excessive latency is indicative of broader network issues

Status Codes

Additional information for specific 5xx status codes is provided below.

Status Code	Description
500 Internal Server	Indicates that the web server experienced an error that prevented it from serving the requested content.
503 Service Unavailable	Indicates that the web server is overloaded or down for maintenance.
504 Gateway Timeout	Indicates that a timely response was not received from the web server. Learn more.

Status Code

Description

500 Internal Server

Indicates that the web server experienced an error that prevented it from serving the requested content.

503 Service Unavailable

Indicates that the web server is overloaded or down for maintenance.

504 Gateway Timeout

Indicates that a timely response was not received from the web server.

Learn more.