[Exim] SMTP AUTH and mail clients again

Hello list,

I write once explaining my problem between exim and different mail readers.
Please, can anyone help me?

I've configured exim with the following properties to allow relay using
authentification:

host_auth_accept_relay = *
auth_over_tls_hosts = *
tls_advertise_hosts = *
tls_certificate = /etc/exim/certificate
tls_privatekey = /etc/exim/privatekey

fixed_plain:
     driver = plaintext
     public_name = PLAIN
     server_condition = ${if and{{eq{$2}{user}}{eq{$3}{password}}}{yes}{no}}
     server_set_id = $2

fixed_login:
     driver = plaintext
     public_name = LOGIN
     server_prompts = User Name : Password
     server_condition = ${if and {{eq{$1}{user}}{eq{$2}{password}}}{yes}{no}}
     server_set_id = $1

fixed_cram:
    driver = cram_md5
    public_name = CRAM-MD5
    server_secret = ${if eq{$1}{user}{password}fail}
    client_name = user
    client_secret = password

Now I'm probing with differents mail readers and I have the following problems:

1- Netscape 6.2: It works. The first time to connect to the smtp server, it
ask for accepting the machine certificate and ask for the user and password
correctly (using ssl).

2- Eudora 5.1: Not works. When I use it gives me this error message:
         Error reading from network      Cause: (0)

3- Netscape 4.7: Not works, in windows, but works in linux. When I use it
gives me the following error message:
         An error occurring while sending mail: SMTP error. The server
responded:
                 (null)

4- Outlook express 5: Not works. It ask me the user and password from the
smtp machine before the connection to the machine and it responds:
         550 relaying to <hector.garcia@???> prohibited by
administrator', Port: 25,
         Security (SSL): No, Server error: 550, Error number: 0x800CCC79

Any ideas to solve this problems?

P.D.: All mail readers are in the same machine, except the linux machine.
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Héctor Garcia Peris
Dpto. Informática
Instituto Valenciano de Investigaciones Económicas S.A. (Ivie)
C/ Guardia Civil, 22 esc-2 1º 46020 - Valencia (Spain)
Tfno.: +34 - 963190050 / +34 - 963930816
Fax.: +34 - 963190055 / +34 - 963930856
e-mail: hector.garcia@???
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