Practicalities for the USI community

Emails to a large number of external recipients

It is important to follow suggestions and rules to send emails to a large number of recipients outside of USI. Sometimes, mails sent from an USI address to external recipients may end up in the SPAM folder or be immediately deleted without notice.

This might happened to newsletters, surveys and other promotional messages that do not comply to basic group email rules. For example:

  • Difficult to unsubscribe
    If the unsubscribe process from a list is made difficult, the recipient might flag the message as SPAM. This will make the delivery process of emails coming from the USI domain difficult, and cause more damage than a single unsubscribe from a list. It is important to always include the unsubscribe link from your email list.
  • Email lists not updated
    People change their email address regularly. If the message remains unread or if there is no answer, the address is probably old and should be removed from the mailing list. Emails sent repeatedly to people who no longer read messages are detected, and they damage the reputation of the mailing system.
  • Sending irrelevant emails
    Sending the same message to a mailing list does not provide pertinent information to all recipients. Please consider segmenting and customising your messages to make them more appealing. If you have more than 3 unread messages sent to the same address, it means that the recipient is either not interested in what we have to say, or that the address has changed.

Writing emails to recipients who immediately delete our messages or mark them as SPAM will damage the reputation of the mailing system.


Microsoft criteria, procedures and guidelines

Microsoft, which runs, and, has published the user guidelines to submit emails to its systems.

For some of them your cooperation is required.

Microsoft is committed to provide its users with a reliable and secure web service. For this reason, it has developed a number of recommended policies, processes, and procedures designed to protect users from unwanted, malicious or abusive messages. Those who wish to send e-mails to users will have to read and follow the guidelines on this page, thus avoiding any delivery issues.

  • After receiving a numeric SMTP error response code between 500 and 599, also known as a missed delivery response, the sender should not attempt to send the message again to the same recipient.

    Example of error response:
    550 5.5.0 Requested action not taken: mailbox unavailable.
    If this kind of error is generated, it is forbidden to write to that recipient again. The server will not send the message.
    What should be done: Delete the address from the list.

  • After multiple missed responses, the sender must stop any attempt to send e-mails to that recipient.

    Example of error response:
    450 4.5.0 Mailbox temporarily unavailable.
    If this kind of error is generated several times, it is forbidden to write to that recipient. The server tries to send the message repeatedly and informs the sender of the pending messages and errors.
    What should be done: If the message cannot be delivered, delete the address from the list.

  • The unsubscribe link, both from the single mailing list or from all the lists managed by the sender, must be clearly stated and easy to find and to follow. 

    It is forbidden to write to people who do not wish to be in the mailing list.
    What should be done: It is mandatory to delete all recipients who requested it, and to clearly state in every message how to do it. 

  • Senders are not allowed to use data mining in namespaces on inbox servers. It is basically checking email addresses without actually sending or trying to send messages.

    Microsoft prohibits the verification of mail addresses by fake mail.
    What should be done: Messages must be send through mailing systems who do not use data mining such as our mail service.

All messages also need to comply with government regulations: (true for all USA providers)

E-mails sent to users must fully comply with the regulations and laws governing e-mail communications within the jurisdiction:


New system

To allow members of the academic community to send emails in accordance with the rules stated, the IT Service has developed a system that automates message customisation, tracking of opened messages, and deletes addresses from the mailing lists.

For information on the new system: [email protected].




Updated on: 17 May 2022