diff --git a/swh/vault/backend.py b/swh/vault/backend.py
--- a/swh/vault/backend.py
+++ b/swh/vault/backend.py
@@ -75,7 +75,6 @@
         self.cache = VaultCache(**config["cache"])
         self.scheduler = get_scheduler(**config["scheduler"])
         self.storage = get_storage(**config["storage"])
-        self.smtp_server = smtplib.SMTP(**config.get("smtp", {}))
 
         if "db" not in self.config:
             raise ValueError(
@@ -488,15 +487,17 @@
 
     def _smtp_send(self, msg: MIMEText):
         # Reconnect if needed
+        smtp_server = smtplib.SMTP(**self.config.get("smtp", {}))
         try:
-            status = self.smtp_server.noop()[0]
+            status = smtp_server.noop()[0]
         except smtplib.SMTPException:
             status = -1
         if status != 250:
-            self.smtp_server.connect("localhost", 25)
+            # XXX this is doomed
+            smtp_server.connect("localhost", 25)
 
         # Send the message
-        self.smtp_server.send_message(msg)
+        smtp_server.send_message(msg)
 
     @db_transaction()
     def _cache_expire(self, cond, *args, db=None, cur=None) -> None:
diff --git a/swh/vault/tests/test_backend.py b/swh/vault/tests/test_backend.py
--- a/swh/vault/tests/test_backend.py
+++ b/swh/vault/tests/test_backend.py
@@ -212,10 +212,10 @@
 
     swh_vault.set_status(TEST_TYPE, TEST_SWHID, "done")
 
-    with patch.object(swh_vault, "smtp_server") as m:
+    with patch.object(swh_vault, "_smtp_send") as m:
         swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
 
-        sent_emails = {k[0][0] for k in m.send_message.call_args_list}
+        sent_emails = {k[0][0] for k in m.call_args_list}
         assert {k["To"] for k in sent_emails} == set(emails)
 
         for e in sent_emails:
@@ -327,10 +327,10 @@
     swh_vault.set_status(TEST_TYPE, TEST_SWHID, "failed")
     swh_vault.set_progress(TEST_TYPE, TEST_SWHID, "test error")
 
-    with patch.object(swh_vault, "smtp_server") as m:
+    with patch.object(swh_vault, "_smtp_send") as m:
         swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
 
-        e = [k[0][0] for k in m.send_message.call_args_list][0]
+        e = [k[0][0] for k in m.call_args_list][0]
         assert e["To"] == "a@example.com"
 
         assert "bot@softwareheritage.org" in e["From"]