Error code 520

wav3front

Hi,

This issue is driving me crazy.
I'm getting Error code 520 for one page, on a WP site. This error is a Cloudflare error and indicates issue with server.
What's weird is that when I bypass Cloudflare and access the page directly, it works. However, I doubt if Cloudflare is reporting a false positive.

php log does not report anything.

I need to dig deeper to found out what the actual error is.

Where can I find OLS logs?
Any other idea what logs to check in enhance?

Thanks
Alex

wav3front

It seems that the issue is related to a very large headre response from the server.
https://ibb.co/vkdqYks

Is this related to Enhance?

wav3front

Found it. This was related to Breakdance builder producing huge headers.

deydod

Could you share your fix regarding this issue?

wav3front

Yes!

Breakdance builder has a "Enable rendering performance debugger" switch.
This enabled Server timing API which produces huge headers. Cloudflare does not like huge headers.

Alex

twest

Max Request Header Size can also be increased in the Litespeed config panel (panel not available in OLS yet). LS and Nginx have a pretty good default, and Apache has a much lower default. I found with sites that run ads the ad companies scripts dump a metric shitton of cookie data into the headers, requires bumping the headers limit up. I think for Apache I kicked it up 100% over the default.