How to redirect to a 404 error from a plugin

Hi everyone, I'm trying to redirect to a 404 page from a plugin with this method

/forum/archive/how-to-trigger-a-404-error-from-within-a-plugin-t3198

but nothing is happening...... If you have a solution!

Thank you! Thank you!

you need to declare your function in getSubscribedEvents() function

then

public function onPageNotFound(Event $event)
{
// do your stuff

}

you can check many plugins use that method
... welcome to Grav Community 😀