Cornerstone fails to open editor on any post/page

Support
#1

After a recent update, this Cornerstone error started to occur on every editor page or preview.

Error: “The preview could not load due to the iframe response being incomplete. This is most often related to a plugin conflict, or customizations introducing a PHP error.”

Screenshot:

Version information: Nginx 1.12.2, PHP-FPM 7.0.28, Ubuntu 14.04, Wordpress 4.9.5 (multisite enabled), X 6.0.4, Cornerstone 3.0.4.

This is not being caused by a plugin/theme conflict. It has been check for plugin/theme conflicts. It has been unable to be reproduced in a test environment. There are no thrown PHP errors (IE OOM, max vars, exceptions, etc). There are JS warnings related to the loading of Cornerstone content.

JS Console:

[Warning] preview-frame::update-aborted (cs.js, line 6837)
Object

error: true

message: "incomplete"

response: "↵↵↵↵↵↵<!DOCTYPE html>↵↵<html class=\"no-js\" lang=\"en-US\">↵↵<head>↵ ↵<meta charset=\"UTF-8\">↵<meta name=\"viewport…"

Object Prototype

Already ruled out:

  • Plugin/theme conflicts
  • PHP configuration faults (memory is fine, max vars is fine, etc)
  • PHP exceptions/Wordpress hard conflicts
  • Browser (Tested on latest versions of FF, Chrome, Safari at time of posting).
  • Multisite errors
WPML - Pro v3 - The preview could not load due to the iframe response being incomplete
#2

Hi There,

Thanks for writing in!

As I do not have access to your website dashboard I will suggest few troubleshooting steps that you should follow, you already followed few of them which I will not include anymore:

The message can be caused by the following:
Incorrect setup of SSL. If you have an SSL certificate on your site. You should have the WordPress Site URL and Address URL settings set to HTTPS if you are loading the builder via HTTPS. This can be checked via your wp-admin > general > settings. If you aren’t using SSL you can ignore this step.

Caching. If you have a caching plugin activated or any form of server side caching please disable it to test for any possible conflicts. If you have server side caching or aren’t sure if you do, your host should be able to advise of this and disable it for testing purposes on your account.

Cloudflare. If you are using Cloudflare please disable this for testing purposes. Cloudflare by default enables an auto minfication function to compress the JS and CSS files of the theme. As the theme already serves minified files, re-minifying said files only causes to break the entire site.

Custom code syntax error. If you have a child theme, please enable the child theme and check if the issue still exists. If you have entered any custom JS or CSS into their respective editors. Please review the code for any syntax errors. A mis-placed semi-colon or a missing bracket will cause the issue you’re seeing.
If you could please try the above and if you still have the issue we’d be more than happy to assist.

Please provide following information:
Set it as Secure Note

  • Link to your site
  • WordPress Admin username / password
  • FTP credentials
    All the best!

Thank you.

#3

Information provided via a secure note. None of the cases listed are the cause as there is no caching on this site, no CloudFlare or similar reverse proxies, no ‘custom code’, and TLS is properly implemented via wp-config and wp-admin.
Thanks for the quick response!

#4

Hi There,

Thanks for the details!

I can confirm the issue, and found there is some JS error on your site.

Which may due to custom code or any third-party plugins. Also, I am unable to check custom JS code as the Global JS panel is missing on your site.

Normal setup

To troublewshoot the issue I would like you to please disable all the thirdparty plugins and reinstall the theme by deleting all the file and cornerstone.

As this is a live site we can’t perform the action on our end, please take a backup and perform the action as mentioned. Let us know how this goes.

Thanks

#5

Global JS is appearing for me in both Chrome and Safari.

Trying reinstalling the theme now. Will update shortly.

#6

Manual and automated installation did not solve the issue. Issue now appears to be related to the plugin “Search & Filter Pro”. Contacting plugin author, thanks!

#7

Hi there,

Thank you for informing us about the 3rd party plugin conflict. As you may already know the third party plugins conflicts are outside of our support scope and we will not be able to give proper suggestions and code fixes as we are not familiar with ins and outs of the plugins.

As you mentioned the best way is to contact the plug-in developer to follow up the case.

Thank you for your understanding.

#8

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