I have been locked out of my own website by defender, I received the following email - We've just locked out the host 18.104.22.168 from https://www.pro***.com due to more than 10 404 requests for the file /wp-content/plugins/wordpress-chat/wpmudev-chat-ajax.php. They have been locked out for 300 seconds.
In the admin dashboard it shows:
However, the file exists in the server:
Is there a reason why this happened in the first place? And how can I avoid this in the future?