ClassicPress + Divi 4.0 Cannot load JS resource/404

With Divi 4.0 ClassicPress is not loading the front end builder or new theme builder released in Divi 4.0. After working with Elegant Themes Support, they are advising the error is the same JS error and that this is an issue with the core of ClassicPress. There are no plugins active, and safe mode is on to ignore all custom code (which is only CSS.)

Expected behavior

When editing a page, and choosing to build on the front end, the Divi Builder should load the page.
For the Theme Builder, hovering over Divi from the side menu, and then clicking Theme Builder, the theme builder options should load.

Current behavior

Currently, both the front end builder and the theme builder do not load. The front end builder pre-loader icon spins endlessly. The them builder loads a completely blank page.

Screenshot: Theme Builder

Possible solution

Elegant Themes has suggested this is an issue with the core not being compatible. I don’t have any other helpful information. Sorry.

Steps to reproduce

Provide a link to a live example, or an unambiguous set of steps to reproduce
this bug. Include code to reproduce, if relevant.

  1. Install Divi 4.0.x on ClassicPress.
  2. Add a new page and create it as a test page
  3. Click to “Build on the Front End”
  4. Exit the page.
  5. On the side menu, hover over Divi
  6. Select Theme Builder
  7. I can also give access to the back end of my test site, but cannot post that login info publicly.


How has this issue affected you?
I cannot use the front end builder nor the theme builder to build pages

What are you trying to accomplish?
I’d like to be able to use the front end builder and theme builder for building pages.

Providing context helps us come up with a solution that is most useful in the
real world.


Hi @LeslieM and welcome.

This thread appears to discuss a similar issue with some potential workarounds: Divi Builder does no longer work with CP

ClassicPress started from WordPress 4.9.x as a base, and we haven’t made any changes to the functions or hooks that plugins use internally. This means “an incompatibility with core” is unlikely to be the right answer.

I would recommend that you confirm the same issue still affects WordPress 4.9.x (we can provide steps to move your site back to this version if you need them) and then take it up with the Divi support team. This will take ClassicPress out of the equation and make it easier for their team to find the issue.

Other people who use Divi will be able to help more, but I’m not sure how much we can do about vendors who claim to support the version of WordPress that ClassicPress is based on, but then release code that doesn’t live up to this claim.

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Thank you for your help. This is not in my wheelhouse. If you can provide steps so I can move to WordPress 4.9.x that would be great. I’d like to test it. I don’t want to leave CP, though. ET is telling me I don’t need CP because they have an ability to disable Gutenberg built into Divi. But what if I no longer wish to be with Divi? Plugins that disable are not a long term solution, but CP is.

I agree that it is not likely the issue. There have been no updates from CP.

I really do appreciate you stepping in with information.


Sure, the first step is to install the migration plugin. If you already have it installed then you can skip this step. If not, you can download it from here:

Then, go to “Tools > Switch to ClassicPress” and click the “Show advanced controls” button.

It will ask you for a build URL, you can use this one:

Then click the button to roll your site back to WordPress.

When you’re done testing, you can use the same migration plugin to switch your site back to ClassicPress again.


As James has said @LeslieM, this is not an issue with ClassicPress. If you take a look through the thread James linked to, you’ll see that Elegant Themes have generally not been too helpful.

Just to confirm, I have just installed Divi 4 on a clean install of WP 4.9.9 running on PHP 7.2. I allocated a whopping 512MB of memory to WordPress and yet I experienced exactly the same problems as you.

I got this Javascript error:

and these PHP errors:

[22-Oct-2019 18:29:44 UTC] PHP Notice:  Trying to get property 'cat_name' of non-object in \wp-content\themes\Divi\includes\builder\functions.php on line 8641
[22-Oct-2019 18:29:44 UTC] PHP Notice:  Trying to get property 'cat_ID' of non-object in wp-content\themes\Divi\includes\builder\functions.php on line 8642

And just to be doubly certain, I used the System Status in the Divi “Support Center” to check that my installation met requirements. And it did:


So this confirms to me that the problem is purely down to bugs in the Divi code and definitely nothing to do with ClassicPress.

Hope this helps.


Thank you both gentleman. I’m going to go fuss at ET. I’m very disappointed with them.

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@james I’m unable to download the plugin. I click the button to get the file and it says it cannot connect to github. :slight_smile:

I contacted GitHub support and this is fixed now.


Well, I’ve gotten absolutely no where with ET Support. It’s clear they are not going to support CP. The entire conversation with them I feel has become rather toxic and not focused on Support at all. To keep using Divi I will have to move back to WP. :disappointed_relieved:

This bothers me a lot. I believe in CP and the roadmap of work. I really don’t like having to switch b’c of a theme developer. If there is anything I can do to that will help CP grow, please let me know, even if it’s something small. I’m in CompSci courses now and learning more and more to develop myself professionally, too.

Thank you for the assistance you have provided. :100:


Look at the response I just got from ET… different support person.

Hi Leslie! wave

I can confirm that there’s a bug with WordPress 4.9.X that prevented the Visual Builder and the new Theme Builder from working. This is reported and it should be fixed in the next updates, I don’t currently have any specific ETA however it should be very soon.

Sorry for the inconvenience!

Of course this was after being addresses in a very condescending manner. But, they’ve acknowledged it.


Well, well, well. They’ve admitted what we knew all along. As long as they do fix it, then you’re OK for the time being but it’s clear that they have no long term plans to support WP4.9.x.

But you don’t need to give up on Divi (just yet) or move back to WP. You can carry on using an older version of Divi (like I’m doing on a couple of sites). Version 3.20.2 seems to work fine for me but I think it’s pot luck what works and what doesn’t. Find a version that works and stick with it unless you desperately need features in later versions.

From what I’ve seen of Divi 4, it’s even more bloated. For example, Divi 3.20.2 is 6.8MB (compressed) whereas Divi 4 is 8.6MB. Perhaps you could stick with an older version of Divi until you find a lighter alternative that complements the ClassicPress goal of reducing bloat?

Just a thought. :slightly_smiling_face:


Great advice. On my test site I can do whatever. The others are client sites. When the time comes to r/d them, I want to go headless. I could use CP for the backend and Angular Universal for the front.


This is going to be an increasingly useful option I think. I did the same thing with my favourite theme (GeneratePress). I could see they were starting to include Gutenberg functionality so I just made my own clone of the theme and stripped out all the stuff I didn’t need (eg all the upsell links).

The only problem is with security fixes that might be introduced later… we won’t be getting those.


Hi @LeslieM, another Divi user here. As far as my developer has been able to discern, there appears to be an error where they are not calling the needed libraries to make Divi work on WP pre-Gutenberg. I’ve also brought this to their attention and have been met with the same condescending attitude – which, frankly, I’ve found to be systemic with most theme developers until I could demonstrate that I did indeed know what I was talking about.

At any rate – I’m glad to hear they have finally acknowledged that there is an issue at all and that they intend to fix it; it looks like there’s been quite a few bugs in 4.0 (judging from the way they keep releasing updates) and I suppose we can be happy that they’re making an effort.

I would love to see Divi offer support for ClassicPress but it will take some number of us continually pinging them and asking for the support before we will make ourselves heard. Thank you for taking the time to work with them even with their poor attitude.


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Good day! It’s a pleasure to make your acquaintance.

I had also found a compatibility issues with Smush and was told there wasn’t. However, 2 updates later ET has resolved the issue with Smush and it’s referenced in their change logs. There have been numerous challenges with the release of 4.0. It could be largely mitigated by their own community if they allowed vendors who make Divi specific software (plugins, etc) to beta test. ET could then integrate issues into their official CI/CD channel for development. Instead, their approach is very reactive. The MVP of their major updates are very buggy. These are only my thoughts and observations. Not necessarily true or accurate. I have really liked Divi over the years. That being said, I have rarely had an issue with Divi in the past. I was shocked at the tone of one of the support persons.

Are you in the Phoenix area? I noticed your alias. :slight_smile:

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I agree – I enjoy using Divi and it has really helped me grow my business over the last couple of years. However, Gutenberg has caused some major issues for my business model – which is why I got involved with ClassicPress.

Glad you’re here – this is a fantastic community and I’m glad to be a part of it all.

Although I have family out that way, I’m not in the Phoenix area. My business name is BlueSkyPhoenix, a reference to the story of the Phoenix. :slight_smile:

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Same here. My clients do not care for not want anything to do with the Gutenberg roadmap and WP is going.

I’m in Phoenix. :slight_smile:


As I am doing with Genesis Framework.

I hope, someone will fork most used themes, builders, frameworks to pre-bloated state.

In case of Divi, I have a strong personal dislike because of mess in code output. As a builder, Elementor is much better, IMHO. And Dynamik is even better (I’d said, the best, but it uses a very different approach).


I’m not particularly a fan of Divi either but I’ve used it on a couple of sites because the client specifically asked for it. And it looks like I’m soon to inherit another site built using Divi.

When I build sites from scratch, I tend to use Understrap but as this itself is based on Automattic’s Underscores, I think it’s time for a change.

Anyone used Roots?

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The Force Majeure event: inheritance. :slight_smile: The problem: you can’t change clients testament.

To me, Divi and Business-focused in the same sentence sound strange, in the best case.