When I open Dashboard → Replies → Add new reply I get 500 error and this in php logs:

[16-Apr-2025 13:27:10 UTC] PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 262144 bytes) in /Users/chefranov/Sites/mysite.loc/wp-includes/class-wp-object-cache.php on line 363
[16-Apr-2025 13:27:10 UTC] PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 262144 bytes) in /Users/chefranov/Sites/mysite.loc/wp-includes/class-wp-fatal-error-handler.php on line 37

[@robin-w Moderator 3 days, 9 hours ago]

There are many reasons why this might occur, that are site specific. This is not a known error with bbpress and more likely to be related to either the set up of your site, or it could be a theme or plugin issue

Themes

As a test switch to a default theme such as twentytwenty, and see if this fixes.

Plugins

If that doesn’t work, also deactivate all plugins apart from bbpress and see if this fixes. if it does, re-enable one at a time to see which is causing the error.

If you cannot do this to your site (say because it is live) then use the ‘troubleshooting’ features of this plugin to let you test without affecting other users

Health Check & Troubleshooting

If that does not point to the error, then I’d suggest you contact your host provider for help.

[@chefranov Participant 3 days, 9 hours ago]

I found a plugin that affects this. It’s Advanced Custom Fields Pro. I don’t have any additional fields (ACF), just installed plugin. I created empty site and installed plugins.
Also tried with Free version of ACF and it the same. Could you check this conflict?

STR:
1. Install and activate bbPress
2. Install and activate Advanced Custom Fields (Free or Pro)
3. Open Dashboard → Replies → Add new reply

Expected result: page with creating a new reply
Actual result: 500 error and error about memory leak in php logs

[@chefranov Participant 3 days, 4 hours ago]

I tried this hack

add_action('all', function($tag) {
    static $count = 0;
    if (strpos($tag, 'acf') !== false && $count++ > 300) {
        error_log('ACF hook overflow: ' . $tag);
        exit;
    }
});

and it response:

[17-Apr-2025 10:10:24 UTC] ACF hook overflow: gettext_acf

[@enkoes Participant 3 days, 2 hours ago]

I’m also facing the same issue. When I open Dashboard → Replies → Create new reply, it returns Server Error 503. When I disable ACF(free version), it’s back to normal without error.

[@robin-w Moderator 2 days, 23 hours ago]

This post suggests it has been an issue for a while

Not working with ACF Pro 6.2.8 version.

seems to suggest an issue since version 6.0.5

I’d suggest you raise it again with ACF

Contact

[@chefranov Participant 2 days, 9 hours ago]

I wrote to support and to the ACF forum. Let’s wait for an answer.

[@robin-w Moderator 2 days, 9 hours ago]

thanks, please do post back their response to help others here