Mailboxes with the highest number of emails sent.

Mass email? Look in Sophos reports, server logs, ask users. Stop it: Limit sending, block tools, disable accounts if needed. Talk to them: Explain policies, offer training. Be clear, consistent, proactive!

Thanks for your answer.

The information I want to know is which mailbox sends the greatest number of emails. or a Top of sending mailboxes.

I can't find a report that gives me this information

or a Top of sending mailboxes. I can't find a report or Field that gives me this information

Francisco, today this is not possible, we've added your request to our list of enhancments. We are releasing some Executive Reports and if we can squeeze this request in will attempt. The Executive Reports will allow you to schedule delivery of reports on a time bases. We expect to release this enhancement in Q1CY24 so not too far off.