NinjaFirewall has blocked an attempt to create a user account

Hi there,

I have a Woocommerce Shop running your Plugin.

This morning I received the following mail:

NinjaFirewall has blocked an attempt to create a user account:

Blog: https://my-website.com/
Username: user.name (blocked)
User IP: 71.138.150.23
SCRIPT_FILENAME: /my-website.com/index.php
REQUEST_URI: /?wc-ajax=checkout
Date: M?rz 10, 2024 @ 20:48:16 CET

The PHP backtrace gives:

[0] => Array
(
[file] => /my-website.com/wp-includes/class-wp-hook.php
[line] => 324
[function] => nfw_account_creation
[args] => Array
(
[0] => user.name
)

    )

But in the file /wp-includes/class-wp-hook.php there is no function called nfw_account_creation.

And in the line 324 is the following code: $value = call_user_func_array( $the_[‘function’], $args );

Can you please explain to me, why the attempt to create a user account has been blocked?

Thank you very much

Ingo