diff --git a/mercurial_keyring.py b/mercurial_keyring.py
--- a/mercurial_keyring.py
+++ b/mercurial_keyring.py
@@ -103,7 +103,7 @@ class PasswordStore(object):
             self._format_smtp_key(machine, port, username),
             password)
     def clear_smtp_password(self, machine, port, username):
-        self.set_smtp_password(url, username, "")
+        self.set_smtp_password(machine, port, username, "")
     def _format_smtp_key(self, machine, port, username):
         return "%s@@%s:%s" % (username, machine, str(port))