These days the TIM has modified the settings for sending mail and then all users will have to adapt if they want to send an email via the SMTP of the TIM.

The SMTP has remained the same, however has become mandatory authentication using an account IBOX.

The user account IBOX is your cell number following Questo indirizzo email è protetto dagli spambots. È necessario abilitare JavaScript per vederlo.

If you do not have an account IBOX you can activate it by calling your telephone number on 41901 (surcharge) and follow the instructions.

So once obtained usernames and passwords that you have to set the outgoing mail server requires authentication and enter your credentials.