Cornerstone - 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

[tpengelly]

We are using Godaddy Wordpress Managed Hosting and while building the website we keep receiving “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.” when editing in Cornerstone. It will allow us to change a single element setting and then it freezes with the error when trying to continue with other changes.

We’ve tried turning off all plugins, switching from child to parent theme, turning off Godaddy’s object caching and disabling WP_CACHE, increasing the memory limit, there is no customized JS - nothing seems to be working.

We are using the most recent Pro theme 6.6.3 and running PHP 8.0 and WordPress version 6.7.2

We are really struggling to figure out what is wrong.

[prakash_s]

Hello Tim,

Thanks for writing to us.

Thanks for checking the plugin conflict, To help you with your corners we need to check your settings it would be best if you could copy your live site to the staging server and share the admin login details so we can check it on our end without breaking your live site. 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

Thanks

[tpengelly]

I’ve added the credentials above

[prakash_s]

Hello Tim,

I checked your site on my end and it is working fine on my end. It might be the issue of browser cache I would suggest you please clear your browser cache and recheck it again. I have tested it on the Google Chrome browser version 134.0.6998.166. If the issue still persists please let us know the browser and its version.

Thanks

[tpengelly]

The page will always initially load, but then if you change something more than one time the preview stops working and will then start triggering the preview error.

[tpengelly]

I tried in Chrome as well (same version as you with all browser cache cleared)

[prakash_s]

Hello Tim,

I rechecked your site page and it is working fine. Please ensure that you have not installed any browser extension that is stopping any JS or CSS file from loading. I would suggest you please check on a different system or contact a local developer.

Thanks

[tpengelly]

Our developers here have tried in different browsers and on different systems and still get the same error. To replicate the error try going to the Contact Us page and change the padding of the “Send a message” button and then try to change it back. Then switch or open to a new page and then try going back to the Contact Us page.

[tpengelly]

I’m also wondering if it possible that Godaddy’s CDN may be causing this issue? I think that use Cloudflare.

[Ismael]

Thank you for the update.

We were able to reproduce the issue with the Contact Us page, but we are not yet sure what is causing it. It doesn’t occur on the Test (Copy) page that @prakash_s created. Please try saving the content of the Contact Us page as template, delete the current page, trash it, create a new page, then apply the template. If possible, use a different page title or name, other than Contact Us. Please check this link:

– https://theme.co/docs/template-manager#saving-templates

Let us know the result.

Best regards.

[tpengelly]

Hi Ismael,

I’ll look into doing this. Is it possible that Godaddy’s CDN may be causing this issue though? I think that use Cloudflare.

[Ismael]

We can’t really tell if CDN is causing the issue, but we did notice a 429 error on the Contact Us page. Did you apply any specific configurations or rules for this page, perhaps within the .htaccess file or your CDN settings?

– https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/429

Let us know if recreating the page helped.

[tpengelly]

No, we haven’t done that. Where did you see the 429 error, I’ve not seen that before?

[Ismael]

The 429 error can be seen in the Networks panel, and just now, in the Response tab, we can see that it is asking for human verification (Pagely), which is from GoDaddy.

Please try to contact Pagely for additional assistance: https://support.pagely.com/hc/en-us/articles/114094215332-Contacting-Support

[tpengelly]

I do see under the Headers tab that it is referencing Cloudflare as the server. I’m going to see if we can turn the CDN off and hope that fixes the problem.

[prakash_s]

Hello Tim,

Please let us know how it goes.

Thanks