HTTP 100 Continue vs 520 Web Server Returned an Unknown Error
HTTP 100 (Continue) is a 1xx Informational response, while 520 (Web Server Returned an Unknown Error) is a 5xx Server Error response. 100 indicates that the server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected. In contrast, 520 means that cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
الوصف
The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
متى تراه
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
كيفية الإصلاح
This is an interim response — no fix needed. The client should continue sending the request body.
الوصف
Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
متى تراه
When Cloudflare receives an empty, unknown, or malformed response from the origin.
كيفية الإصلاح
Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.
الفروق الرئيسية
100 is a 1xx Informational response, while 520 is a 5xx Server Error response.
HTTP 100: The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
HTTP 520: Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
You encounter 100 when when a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
You encounter 520 when when Cloudflare receives an empty, unknown, or malformed response from the origin.
متى تستخدم أيًا منهما
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 520 (Web Server Returned an Unknown Error): Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.