Hi @Alfredo_Cosco,
If your PHP is configured to send warning/error messages to the browser, AJAX responses may get PHP warnings inserted into them. This will prevent JSON parsing from happening properly, so you’ll see subrequests not loading.
The best solution is to tinker with your PHP and/or OMP configuration files to ensure that things like deprecation warnings are logged but not sent to the browser. (This is recommended for production use anyway.) See config.inc.php for the display_errors and deprecation_warnings settings, and your php.ini configuration file for e.g. the error_log setting.
Regards,
Alec Smecher
Public Knowledge Project Team