diff --git a/hedgedoc-expire.py b/hedgedoc-expire.py
index 30567a3..64ed766 100644
--- a/hedgedoc-expire.py
+++ b/hedgedoc-expire.py
@@ -196,6 +196,7 @@ class HedgedocExpire:
                     msg = MIMEMultipart()
                     msg['From'] = self.email_sender.mail_from
                     msg['To'] = self.email_from_email_or_profile(note)
+                    msg['Date'] = email.utils.formatdate()
                     msg['Subject'] = f'Your HedgeDoc Note "{note["title"]}" has expired'
                     msg.attach(MIMEText(dedent(f'''\
                         You created the note titled "{note["title"]}" on {note["createdAt"]}.
@@ -301,6 +302,7 @@ class HedgedocExpire:
         msg = MIMEMultipart()
         msg['From'] = self.email_sender.mail_from
         msg['To'] = self.email_sender.mail_from
+        msg['Date'] = email.utils.formatdate()
         msg['Subject'] = f'Hedgedoc Expire: Report'
         msg.attach(MIMEText(dedent(f'''\
             This report shows which notes and revisions would be deleted if expire would be run now.