I’ve previously been in contact with the University (for a stage, a collaboration or a former student’s career…): do I already have an account?
Yes, you do and that’s what you need to use. If you don’t remember it, ask for it writing to account.help [at] unitn.it ()style="text-decoration:none", forwarding a copy of a valid identification document (ID or passport) and specifying the email address which you wish to be registered for the password recovery procedure.