HTTP 100 Continue vs 525 SSL Handshake Failed
HTTP 100 (Continue) is a 1xx Informational response, while 525 (SSL Handshake Failed) 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, 525 means that cloudflare-specific. SSL/TLS handshake with the origin server failed.
Description
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.
When You See It
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
How to Fix
This is an interim response — no fix needed. The client should continue sending the request body.
Description
Cloudflare-specific. SSL/TLS handshake with the origin server failed.
When You See It
When origin SSL certificate is expired, misconfigured, or incompatible.
How to Fix
Check origin SSL certificate validity. Ensure TLS version compatibility. Renew expired certificates.
Key Differences
100 is a 1xx Informational response, while 525 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 525: Cloudflare-specific. SSL/TLS handshake with the origin server failed.
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 525 when when origin SSL certificate is expired, misconfigured, or incompatible.
When to Use Which
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 525 (SSL Handshake Failed): Check origin SSL certificate validity. Ensure TLS version compatibility. Renew expired certificates.