Ftp – Anonymous account in Windows server 2008

I'm trying to add an anonymous access on a IIS Ftp server (v7.5) on windows 2008-r2

I added IUSR account to my folder with full access.
I stopped the firewall on both sides (client and server)

Each time I try to connect from Filezilla (or ftp cli command) with anonymous account, I get :

530-User cannot log in.
 Win32 error:   Logon failure: unknown user name or bad password.
 Error details: An error occured during the authentication process.
530 End
Login failed.

Under cmd.exe, I get this :

Connected to mysite.
220 Microsoft FTP Service
User (mysite:(none)): anonymous
331 Anonymous access allowed, send identity (e-mail name) as password.
Password:
530 User cannot log in.
Login failed.

Update

Sounds weird but now after having open/close the "Anonymous Authentication Credential" window (which, by the way, have the field "password" with three dots, I don't know why)

now I can connect a client but I get this
"Failed to retrieve directory listing"

What the ???