HTTP 406 Not Acceptable vs 525 SSL Handshake Failed
HTTP 406 (Not Acceptable) is a 4xx Client Error response, while 525 (SSL Handshake Failed) is a 5xx Server Error response. 406 indicates that the server cannot produce a response matching the Accept headers sent by the client. In contrast, 525 means that cloudflare-specific. SSL/TLS handshake with the origin server failed.
Description
The server cannot produce a response matching the Accept headers sent by the client.
When You See It
When requesting a content type the server doesn't support (e.g., Accept: application/xml when only JSON is available).
How to Fix
Adjust the Accept header to a format the server supports.
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
406 is a 4xx Client Error response, while 525 is a 5xx Server Error response.
HTTP 406: The server cannot produce a response matching the Accept headers sent by the client.
HTTP 525: Cloudflare-specific. SSL/TLS handshake with the origin server failed.
You encounter 406 when when requesting a content type the server doesn't support (e.g., Accept: application/xml when only JSON is available).
You encounter 525 when when origin SSL certificate is expired, misconfigured, or incompatible.
When to Use Which
For 406 (Not Acceptable): Adjust the Accept header to a format the server supports. For 525 (SSL Handshake Failed): Check origin SSL certificate validity. Ensure TLS version compatibility. Renew expired certificates.