Cant let into the site, why not?

Below is the message I get for this restaurant site I manage. Please let know why it's doing this, and how I can prevent it in the future. I just did a EVENT category post on his site, and now it's not working for us to promote post.

-You have been locked out due to too many attempts to access a file that doesn’t exist.

    Ash

    Hello Victor Urena

    Looks like you have an URL to a file in a page that doesn't exist and you were visiting that file too many times.

    You can temporarily disable Defender via FTP so you can login to your dashboard in the meantime. You can achieve that like so:

    - Navigate to /wp-content/plugins/wp-defender
    - Rename the directory to something else (i.e. wp-defender-disabled).
    - You should now be able to login to WordPress, and you will receive a small error message indicating that the plugin failed to load.

    You can also whitelist your IP from Defender's setting if you'd like by going to Defender -> IP Lockouts -> IP Blacklist and then type your IP in the Whitelist field. Don't forget to hit Update Settings afterwards. This way you won't be locked out in the future, but keep in mind that your website will be accessible from your IP at all times.

    Also, how long you can't access your website depends on the Lockout Time in your Defender settings in IP Lockouts, either under the Login Protection tab or the 404 Detection tab.

    Let me know how this works for you!

    Have a nice day!

    Cheers,
    Ash