Hi,
same problem...
Joomla 4.1.5
Page Builder Pro 4.0.3 (updated vom 3.8.x)
Update:
apache2 - error.log:
[Mon Aug 22 08:35:28.955532 2022] [authz_core:error] [pid xxx] [client xxx] AH01630: client denied by server configuration: /xxx/index.php, referer: http://xxx/de/edit/1
after changing apache2.conf
<Directory /xxx/html>
AllowOverride FileInfo AuthConfig Limit Indexes Options
Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
### change this
# Require method GET POST OPTIONS
### to
Order allow,deny
Allow from all
Require all granted
</Directory>
maybe it helps...