Can you provide a little more information please? This URL is not usually called with a null parameter there, so it seems a little off.

Can you provide the full message and stack trace from the log? Was it a guest or a logged in member who triggered it?

It was a guest, most likely a probe. We found multiple instances of this in the System Logs while we were reviewing for any recent issues. As you can see with the link above, if someone just visits the URL (without the parameter) it triggers the error.

TypeError: IPS\Http\Url::createFromString(): Argument #1 ($url) must be of type string, null given, called in /var/www/html/xxxxx/applications/core/modules/front/system/embed.php on line 58 (0)
#0 /var/www/html/xxxxx/applications/core/modules/front/system/embed.php(58): IPS\Http\Url::createFromString(NULL, false, true)
#1 /var/www/html/xxxxx/system/Dispatcher/Controller.php(139): IPS\core\modules\front\system\embed->manage()
#2 /var/www/html/xxxxx/system/Content/Controller.php(124): IPS\Dispatcher\Controller->execute()
#3 /var/www/html/xxxxx/system/Dispatcher/Dispatcher.php(169): IPS\Content\Controller->execute()
#4 /var/www/html/xxxxx/index.php(16): IPS\Dispatcher->run()
#5 {main}

The log entry was triggered by a guest (Guests)

May 29

The URL of page the error occurred on was https://x.com/index.php?app=core&controller=embed&module=system