ERROR: The preview could not load due to the iframe response being incomplete

Getting this error on a newly duplicated page but have not added any new plugins. Please advise on how to fix?

Hello @Woodany,

Thanks for writing to us.

There might be a few different reasons for this issue, I would suggest you troubleshoot with a few of the common issues before we investigate your settings.

  1. Testing for Plugin Conflict
  2. CSS/JS Customization
  3. Version Compatibility
  4. Permalink Issue
  5. Disabling Cache

If none of the above help, please share your details in a secure note. Please provide the following details

  • WordPress Login URL
  • Admin level username and password

You can find the Secure Note button at the bottom of your posts


Hi there,
sorry but I cannot figure out what to do. Are you able to please take a look?


Hi Brendan,

It appears that you are using an outdated version of the X theme 7.0.4. Please be advised that we have released X 7.2.3 and Cornerstone 4.2.3 a while ago. It is now available in automatic updates. You can now update to this latest version. This latest release contains fixes for several issues so be sure to check out the changelog (

After doing the updates, always remember to clear all caches (if you are using WP Rocket, WP SuperCache, SG Optimizer or W3 Total Cache) when updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.

Kindly let us know how it goes.

Hi Ruenel,
Thanks for the heads up! I have updated X and Cornerstone but the problem persists.

Hi Brendan,

There might be a few different reasons for this issue, I would suggest you troubleshoot the common issues related to it.

1.Plugin Conflict
2.Child Theme Related issue
3.CSS/JS Customization
4.Disabling Cache

If you discover that an issue is coming from a custom code or 3rd party plugin, kindly consult with a developer or contact the plugin author. Please note that we do not provide support for custom codes and 3rd party plugins.
If none of the above helps, please copy your live site to a staging server so we could troubleshoot freely without breaking your live site.
And give us access in the secure note including:

– WordPress Site URL & Login URL
– WordPress Admin username/password

To create a secure note, click the key icon underneath any of your posts.


Thanks Tristup,
I am not really savvy enough to figure out how to check everything via the links you provided sorry but I did create a staging site:

Hi Brendan,

Can you please create a staging and share the credential once that ready to access.


I did already but here it is again:

Hi Brendan,

I have investigated your page and after my thorough inspection, it appears that the cornerstone data has been corrupted already. It was using a classic element containers by the way. I have created a test page instead that exactly have the same layout. Kindly check out the secure note.

If you are satisfied with the test page, you can simply save it as a template and then you can load this template in your Stereotypes and Romance page. To learn more about how you can save and use the template, please check out this documentation:

Hope this helps.

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