Some Zimbra installations require the full email address as the username. If your first attempt fails, try your complete email address (e.g., m.rossi@aslroma4.it ).
The email system for ASL Roma 4 (Azienda Sanitaria Locale Roma 4) is part of the regional Lazio health network. Here are the steps to access your corporate email. Zimbra Mail Login Asl Roma 4