In the mail log from the web server, you can find information about when and from which hosting account attempts were made to send letters without authorization (using the function mail or sendmail), including those where the sending actually failed and the emails were saved in dead.letter file... Letters sent with authorization (via SMTP) are not recorded in this log.
To view the log, open the section “Hosting → Mail from the site»:
Use the search box at the top of the log to filter records.
from 2-00 to 7-00