I've dealing with a problem since November 1st, all reports that are sent as a Excel attachment (.xls) are not sent, not even the email empty. All other formats (PDF, CSV, HTML, inline HTML) are sent without a problem. I thought at first that it was a problem with our email, but I sent the reports to external domains and the same happened. I've already restarted the app server and the SQL server with no changes.

Please help me. I have the version 9.1 built 9105.