diff --git a/rattail_tempmon/server.py b/rattail_tempmon/server.py
index 66b70db..cc9513c 100644
--- a/rattail_tempmon/server.py
+++ b/rattail_tempmon/server.py
@@ -77,9 +77,9 @@ class TempmonServerDaemon(Daemon):
     def check_readings_for_client(self, session, client):
         delay = client.delay or 60
         cutoff = self.now - datetime.timedelta(seconds=delay + 60)
-        online = False
+        online = True
         for probe in client.enabled_probes():
-            online = bool(self.check_readings_for_probe(session, probe, cutoff))
+            online = online and bool(self.check_readings_for_probe(session, probe, cutoff))
         if not online and client.online:
             log.info("marking client as OFFLINE: {}".format(client))
             client.online = False