520 Errors + Error Logs

A couple of days ago, I received a CF email stating that:

  1. LifeYounique.com had a 1200% increase in server error rate (520 errors)
  2. ChurchPivvot.com had a 750% increase in server error rate (520 and 502 errors)

Both sites are WordPress sites hosted on WPEngine (SSLs configured through WPE).

I connected with WPE support and below is their response:

Is there any way for me to figure out what happened on November 21 through some type of audit/logging on CF’s dashboard?

Error 520: web server returns an unknown error

Error 520 occurs when the origin server returns an empty, unknown, or unexpected response to Cloudflare.

Resolution

A quick workaround while further investigating 520 errors is to either grey cloud the DNS record in the Cloudflare DNS app or temporarily pause Cloudflare.

Contact your hosting provider or site administrator and request a review of your origin web server error logs for crashes and to check for these common causes:

  • Origin web server application crashes
  • Cloudflare IPs not allowed at your origin
  • Headers exceeding 16 KB (typically due to too many cookies)
  • An empty response from the origin web server that lacks an HTTP status code or response body
  • Missing response headers or origin web server not returning proper HTTP error responses

520 errors are prevalent with certain PHP applications that crash the origin web server.

If 520 errors continue after contacting your hosting provider or site administrator, provide the following information to Cloudflare Support:

Thanks for the quick response! I already have contacted my hosting company and they don’t see any errors on the web server side of things. I was mainly interested if there is a log/audit trail anywhere on the backend of CF that I could see what individual errors were triggered and when?

The “DNS” tab in your dashboard should work! This will show you a breakdown of the most commonly returned response codes and show when they were returned!

The error seems to throw enough information to me.
It means that something on your software broke and is erroring. What causes the faulty service is out of the scope of CF and your hosting (unless it’s managed).

The error can come from anywhere; I’d rather not take a blind guess and just advice you to check which software is causing these errors in your backend.

Thank you! I couldn’t find this anywhere in the documentation. Much appreciated!

Glad I could help!

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