diff --git a/cronitor/monitor.py b/cronitor/monitor.py
index 6283ac6..cf7ea59 100644
--- a/cronitor/monitor.py
+++ b/cronitor/monitor.py
@@ -156,7 +156,7 @@ def ping(self, **params):
         return self._req.get(url=self._ping_api_url(), params=self._clean_params(params), timeout=5, headers=self._headers)
 
     def ok(self):
-        self.ping(state=cronitor.Event.ok)
+        self.ping(state=cronitor.State.OK)
 
     def pause(self, hours):
         if not self.api_key: