diff --git a/mercurial_keyring.py b/mercurial_keyring.py
--- a/mercurial_keyring.py
+++ b/mercurial_keyring.py
@@ -620,7 +620,9 @@ def keyring_supported_smtp(ui, username)
             raise util.Abort(_('invalid smtp.verifycert configuration: %s')
                              % (verifycert))
         verifycert = False
-    if (starttls or smtps) and verifycert:
+    if getattr(sslutil, 'sslkwargs', None) is None:
+        sslkwargs = None
+    elif (starttls or smtps) and verifycert:
         sslkwargs = sslutil.sslkwargs(ui, mailhost)
     else:
         sslkwargs = {}
@@ -628,12 +630,16 @@ def keyring_supported_smtp(ui, username)
         ui.note(_('(using smtps)\n'))
 
         # mercurial 3.8 added a mandatory host arg
-        if 'host' in SMTPS.__init__.__code__.co_varnames:
+        if not sslkwargs:
+            s = SMTPS(ui, local_hostname=local_hostname, host=mailhost)
+        elif 'host' in SMTPS.__init__.__code__.co_varnames:
             s = SMTPS(sslkwargs, local_hostname=local_hostname, host=mailhost)
         else:
             s = SMTPS(sslkwargs, local_hostname=local_hostname)
     elif starttls:
-        if 'host' in STARTTLS.__init__.__code__.co_varnames:
+        if not sslkwargs:
+            s = STARTTLS(ui, local_hostname=local_hostname, host=mailhost)
+        elif 'host' in STARTTLS.__init__.__code__.co_varnames:
             s = STARTTLS(sslkwargs, local_hostname=local_hostname, host=mailhost)
         else:
             s = STARTTLS(sslkwargs, local_hostname=local_hostname)
@@ -654,7 +660,10 @@ def keyring_supported_smtp(ui, username)
         s.ehlo()
     if (starttls or smtps) and verifycert:
         ui.note(_('(verifying remote certificate)\n'))
-        sslutil.validator(ui, mailhost)(s.sock, verifycert == 'strict')
+        if getattr(sslutil, 'validatesocket', None):
+            sslutil.validatesocket(s.sock)
+        else:
+            validator(ui, mailhost)(s.sock, verifycert == 'strict')
 
     # >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
     stored = password = password_store.get_smtp_password(