"The preview HTML did not include a closing </html>; tag. It may fail to load or work properly."

With the last update, we have been receiving this error message.

"The preview HTML did not include a closing ; tag. It may fail to load or work properly.”

We have followed the recommended steps (deactivating plugins, clearing cache, etc), and continue to have issues. Please let me know if there are additional steps to take, and when I should escalate this issue. We are stuck without the ability to update.

Thanks for your help - Matt

Hi Matt,

Thanks for writing in! Can you please try switching to your skeleton mode of that page and then inspect your elements and see if you have any HTML without closing tags. Specially check your Text elements and Raw content elements where you can add custom HTML.

If the issue still persist, try following the troubleshooting guidelines below.

  1. Ensure everything is up to date according to our version compatibility list here. Please follow the best practices when updating your theme and plugins. Click here for more information.
  2. Go to X > Settings and click on the Clear Style Cache button.
  3. If you’re using a CDN(ex: CloudFlare), please clear the CDN’s cache and disable optimization services. For the CloudFlare you also need to follow the steps below besides the developer mode: https://xthemetips.com/using-cloudflare-rocket-loader-with-x-pro-and-x5/928/1
  4. Test for a plugin conflict. You can do this by deactivating all third-party plugins, and see if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
  5. Remove custom CSS and Javascript from the options or Child Theme and test the case.
  6. Switch to the parent theme to check if the issue persists.
  7. Turn off all the cache plugins.
  8. Reset your htaccess file by renaming it to .htaccess-bak. Then in WP Admin Menu, go to Settings > Permalinks and just click the Save Changes button.
  9. Increase the PHP Memory Limit of your server. Click here for more detailed information and how to increase the PHP memory limit.

If you still have problems kindly get back to us with the result of the steps above and URL/User/Pass of your WordPress dashboard using the Secure Note functionality of the post to follow up the case.

Thank you.

Hi Matt,

I checked your Server info and can see you have not increased your memory limit as recommended by my colleague.

Please contact your hosting provider and request to increase the following.

memory_limit to at least 256M but we recommend 512M
max_execution time to at least 300s

Then request to update php version to at least Version 7.2 or greater as required by wordpress.

You can also try switching to wordpress default twentyseventeen theme to check if it is a theme related issue.


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Hello Max,

Thanks for updating the thread.

Can you please share website login details in secure note for us to take a closer look.


Hi Matt,

I checked and it’s due to the theme itself, the ajax respond or preview is empty without any HTML code. But activating another theme fixes the issue.

It appears the theme is a custom one, please contact the theme developer about this issue. Unfortunately, I’m not sure how that theme works so I can’t offer any insight about any incompatibilities.


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Hi Max,

May I know the details of the editing issue of the map? Please check it here https://theme.co/apex/forum/t/elements-map-element/10231 in case you’re referring of editing the options.

If it has an error, then please provide a video recording so we could try reproducing it on our end.