Added missing string to verification failed Message

CL-541

plugins/UM3NetworkPrinting/LegacyUM3OutputDevice.py

@@ -91,7 +91,7 @@ class LegacyUM3OutputDevice(NetworkedPrinterOutputDevice):
                                                          title=i18n_catalog.i18nc("@info:title",
                                                                                   "Authentication status"))
 
-        self._authentication_failed_message = Message(i18n_catalog.i18nc("@info:status", ""),
+        self._authentication_failed_message = Message(i18n_catalog.i18nc("@info:status", "Authentication failed"),
                                                       title=i18n_catalog.i18nc("@info:title", "Authentication Status"))
         self._authentication_failed_message.addAction("Retry", i18n_catalog.i18nc("@action:button", "Retry"), None,
                                                       i18n_catalog.i18nc("@info:tooltip", "Re-send the access request"))