Thank you @teraßyte and @Jim M,
here is the log
[09-Apr-2024 18:00:02 UTC] PHP Fatal error: Uncaught Error: Class "Patterns\Singleton" not found in /home/studio154/public_html/forumdifotografia.com/system/Request/Request.php:23
Stack trace:
#0 /home/studio154/public_html/forumdifotografia.com/init.php(756): require_once()
#1 /home/studio154/public_html/forumdifotografia.com/system/Log/Log.php(106): IPS\IPS::autoloader('IPS\\Request')
#2 /home/studio154/public_html/forumdifotografia.com/init.php(1036): IPS\_Log::log('Error: Class "I...', 'uncaught_except...')
#3 [internal function]: IPS\IPS::exceptionHandler(Object(Error))
#4 {main}
thrown in /home/studio154/public_html/forumdifotografia.com/system/Request/Request.php on line 23