We recently upgraded from CE 2.4.2 to 2.4.3p1 and we face a major issue with Page Builder. We are no longer capable of saving product, pages, blocks, ... due to Page Builder.

On save, if we have modified any Page Builder content, there are no communication with the server, but a lock with an infinite spinning icon.

We receive [ERROR] Page Builder was rendering for 5 seconds without releasing locks. in the browser console. We have tested same issue with Chrome & Firefox.

Any clue of how to solve this issue or where to investigate to find some code/settings triggering this ?

Thanks Yannick

2 Answers 2


Seems as if you are experiencing a very slow admin. I had some issues myself and applied the following command:

bin/magento config:set system/security/max_session_size_admin 512000

Found this solution on: Upgrade to magento 2.4.3 - Backend is very slow

  • This problem seems not related to the slow admin as it seems to be a pure client js problem as the client do not initiate any request to the server on save and that there is no issue if page builder content is not modified. Note that max_session_size_admin on my side is the same as yours.
    – ydessert
    Oct 21, 2021 at 14:18

This error can happen when you have either custom content-types or overwritten the master.html master_template. If you are missing attr="data.main.attributes" in the the template it will not render and produce this error.

In my case I've had the following master.html:

<div class="relative">

But adding attr="data.main.attributes" to my root element fixed the issue and the page saved again:

<div class="relative" attr="data.main.attributes">

In general this error seems to happen if the pagebuilder is unable to render the final result for some reason.

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