[Dovecot] Fix invalid rcpt when no bcc is set, fixes #3576

data/Dockerfiles/dovecot/quarantine_notify.py

@@ -86,7 +86,10 @@ def notify_rcpt(rcpt, msg_count, quarantine_acl):
       msg['To'] = str(rcpt)
       bcc = r.get('Q_BCC') or ""
       text = msg.as_string()
-      server.sendmail(msg['From'], [str(rcpt)] + [str(bcc)], text)
+      if bcc == '':
+        server.sendmail(msg['From'], str(rcpt), text)
+      else:
+        server.sendmail(msg['From'], [str(rcpt)] + [str(bcc)], text)
       server.quit()
       for res in meta_query:
         query_mysql('UPDATE quarantine SET notified = 1 WHERE id = "%d"' % (res['id']), update = True)