diff --git a/ns8_backup_monitor/notifier.py b/ns8_backup_monitor/notifier.py
index ed3fa0a..8c4a8b0 100644
--- a/ns8_backup_monitor/notifier.py
+++ b/ns8_backup_monitor/notifier.py
@@ -6,6 +6,11 @@ Formats a human-readable HTML + text email based on:
   - correlation outcome (SUCCESS / PARTIAL / REPO_FAILURE)
   - per-module statuses
   - repository check results (if run)
+
+SMTP configuration is resolved via smtp_config.resolve_smtp_config():
+  1. NS8 cluster Redis (cluster/mail_settings) - same relay used by NS8 itself
+  2. config.yml [smtp] section
+  3. localhost:25 fallback
 """
 
 import logging
@@ -15,9 +20,11 @@ from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from typing import Optional
 
+from .smtp_config import resolve_smtp_config
+
 log = logging.getLogger(__name__)
 
-OUTCOME_EMOJI = {
+OUTCOME_LABEL = {
     "SUCCESS": "OK",
     "PARTIAL": "WARNING",
     "REPO_FAILURE": "CRITICAL",
@@ -33,7 +40,7 @@ OUTCOME_COLOR = {
 def _build_text(correlation: dict, repo_status: Optional[dict]) -> str:
     outcome = correlation["outcome"]
     lines = [
-        f"NS8 Backup Monitor - {OUTCOME_EMOJI[outcome]}: {outcome}",
+        f"NS8 Backup Monitor - {OUTCOME_LABEL[outcome]}: {outcome}",
         f"Time: {datetime.now(timezone.utc).isoformat()}",
         f"Plans checked: {', '.join(correlation.get('backup_ids', []))}",
         f"Modules: {correlation['succeeded']} OK / {correlation['failed']} FAILED / {correlation['total']} total",
@@ -60,10 +67,10 @@ def _build_text(correlation: dict, repo_status: Optional[dict]) -> str:
     return "\n".join(lines)
 
 
-def _build_html(correlation: dict, repo_status: Optional[dict]) -> str:
+def _build_html(correlation: dict, repo_status: Optional[dict], smtp_source: str) -> str:
     outcome = correlation["outcome"]
     color = OUTCOME_COLOR[outcome]
-    label = OUTCOME_EMOJI[outcome]
+    label = OUTCOME_LABEL[outcome]
     ts = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
     plan_ids = ", ".join(correlation.get("backup_ids", [])) or "N/A"
 
@@ -131,6 +138,7 @@ def _build_html(correlation: dict, repo_status: Optional[dict]) -> str:
           <tbody>{rows}</tbody>
         </table>
         {repo_section}
+        <p style="color:#aaa;font-size:11px;margin-top:24px">Sent via {smtp_source}</p>
       </div>
     </body></html>
     """
@@ -145,15 +153,20 @@ def send_notification(
 ):
     outcome = correlation["outcome"]
     mail_cfg = config.get("mail", {})
-    smtp_cfg = config.get("smtp", {})
-
-    mail_from = mail_cfg.get("from", "ns8-backup-monitor@localhost")
-    mail_to = mail_cfg.get("to", [])
     subject_prefix = mail_cfg.get("subject_prefix", "[NS8 Backup]")
-    subject = f"{subject_prefix} {OUTCOME_EMOJI[outcome]}: {outcome} - {datetime.now(timezone.utc).strftime('%Y-%m-%d')}"
+    subject = f"{subject_prefix} {OUTCOME_LABEL[outcome]}: {outcome} - {datetime.now(timezone.utc).strftime('%Y-%m-%d')}"
+
+    mail_to = mail_cfg.get("to", [])
+    if not mail_to:
+        log.error("No mail.to recipients configured in config.yml - cannot send notification")
+        return
+
+    # Resolve SMTP: NS8 Redis relay -> config.yml -> localhost:25
+    smtp_cfg, mail_from = resolve_smtp_config(config)
+    smtp_source = f"{smtp_cfg['host']}:{smtp_cfg['port']}"
 
     text_body = _build_text(correlation, repo_status)
-    html_body = _build_html(correlation, repo_status)
+    html_body = _build_html(correlation, repo_status, smtp_source)
 
     msg = MIMEMultipart("alternative")
     msg["Subject"] = subject
@@ -180,6 +193,6 @@ def send_notification(
             smtp.login(username, password)
         smtp.sendmail(mail_from, mail_to, msg.as_string())
         smtp.quit()
-        log.info(f"Notification sent: {subject} -> {mail_to}")
+        log.info(f"Notification sent: {subject} -> {mail_to} (via {smtp_source})")
     except Exception as e:
-        log.error(f"Failed to send notification: {e}")
+        log.error(f"Failed to send notification via {smtp_source}: {e}")