diff --git a/src/calng/CalibrationManager.py b/src/calng/CalibrationManager.py
index a56ddfe121901c6b0b2fbc25d632312e6750db60..873b3dae23d3de3d4c74a1504954ea5f76994494 100644
--- a/src/calng/CalibrationManager.py
+++ b/src/calng/CalibrationManager.py
@@ -1198,7 +1198,7 @@ class CalibrationManager(DeviceClientBase, Device):
         all_req_servers = set(server_by_group.values()).union(
             server_by_layer.values())
 
-        if set(all_req_servers) < set(up_servers):
+        if set(all_req_servers) > set(up_servers):
             return self._set_error('One or more device servers are not '
                                    'listed in the device servers '
                                    'configuration')