Getting 520 errors with Cloudflare? Read this.

HI David

I have been working with Cloudflare as to why I am getting 520 error when editing posts in WordPress.

They are saying the plugin is causing large response headers which exceeds the 8kb limit CloudFlare allows.

Do you know why the plugin is creating large response headers?

Hello
The error message is showing upstream sent too big header while reading response header from upstream.
{
“_index”: “nginx-2016.07.28”,
“_type”: “nginx”,
“_id”: “AVYwIPi97pP_CcHnwOhm”,
“_score”: null,
“_source”: {
“id”: “2c962c0e8d9351eb”,
“timestamp”: “2016-07-28T06:11:17Z”,
“count”: 1,
“server”: “47m18”,
“flserver”: “47m18”,
“cacheserver”: “47c18”,
“severity”: “error”,
“pid”: “5900”,
“connectionId”: “13759077”,
“message”: “upstream sent too big header while reading response header from upstream”,
“client”: “xxx.xxx.xxx.xx”,
“request”: “GET /wp-admin/post.php?post=146668&action=edit HTTP/1.1”,
upstream”: “https://xxx.xxx.xxx.xxx/wp-admin/post.php?post=146668&action=edit,
“host”: “www.xxx.com”,
“location”: {
“colo”: “xxx”,
“coloId”: 47,
“coloGeo”: [
144.9631,
-37.8136
]
}
},
As shown in the above the upstream xxx.xxx.xxx.xx is sending too big a response header to CF server. Your web server is returning response headers exceeding CloudFlare’s header size limit (over 8kb). We are unable to change the response size limit.

Hi Dave & cgold,

An interesting breakdown.

This is, unfortunately, not my field, but I am seeing the rapid delivery of pages on the sites I work on due to the implementation of this plugin.

I hope that a resolution regarding the oversized headers and CloudFlare can be resolved; I hope to use this plugin as a standard on all the sites we work on, but unfortunately they all use CloudFlare.

Best regards,
Duncan

One of the upcoming changes tries to limit the plugin’s headers to 4k, leaving 4k for all the other response headers the web server, PHP, and other software want to add.

Wonderful, thank you Dave – I look forward to making use of it!

Hi Duncan, When will this plugin be available? Thanks