diff --git a/amperfied/integrationpluginamperfied.cpp b/amperfied/integrationpluginamperfied.cpp
index 6e6121b..817fc1f 100644
--- a/amperfied/integrationpluginamperfied.cpp
+++ b/amperfied/integrationpluginamperfied.cpp
@@ -270,6 +270,11 @@ void IntegrationPluginAmperfied::setupRtuConnection(ThingSetupInfo *info)
 {
     Thing *thing = info->thing();
     ModbusRtuMaster *master = hardwareManager()->modbusRtuResource()->getModbusRtuMaster(thing->paramValue(energyControlThingRtuMasterParamTypeId).toUuid());
+    if (!master) {
+        qCWarning(dcAmperfied()) << "The Modbus Master is not available any more.";
+        info->finish(Thing::ThingErrorHardwareNotAvailable, QT_TR_NOOP("The modbus RTU connection is not available."));
+        return;
+    }
     quint16 slaveId = thing->paramValue(energyControlThingSlaveIdParamTypeId).toUInt();
     AmperfiedModbusRtuConnection *connection = new AmperfiedModbusRtuConnection(master, slaveId, thing);