diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 038ac1f219..8489e05358 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -6013,11 +6013,11 @@ nm_device_state_changed (NMDevice *device,
 		nm_dispatcher_call (DISPATCHER_ACTION_UP, nm_act_request_get_connection (req), device, NULL, NULL);
 		break;
 	case NM_DEVICE_STATE_FAILED:
-		connection = nm_act_request_get_connection (req);
+		connection = nm_device_get_connection (device);
 		nm_log_warn (LOGD_DEVICE | LOGD_WIFI,
 		             "Activation (%s) failed for connection '%s'",
 		             nm_device_get_iface (device),
-		             nm_connection_get_id (connection));
+		             connection ? nm_connection_get_id (connection) : "<unknown>");
 
 		/* Notify any slaves of the unexpected failure */
 		nm_device_master_release_slaves (device, TRUE);
@@ -6027,7 +6027,7 @@ nm_device_state_changed (NMDevice *device,
 		 * failed (zero timestamp), connections that succeeded (non-zero timestamp),
 		 * and those we haven't tried yet (no timestamp).
 		 */
-		if (!nm_settings_connection_get_timestamp (NM_SETTINGS_CONNECTION (connection), NULL)) {
+		if (connection && !nm_settings_connection_get_timestamp (NM_SETTINGS_CONNECTION (connection), NULL)) {
 			nm_settings_connection_update_timestamp (NM_SETTINGS_CONNECTION (connection),
 			                                         (guint64) 0,
 			                                         TRUE);
diff --git a/src/settings/nm-settings-connection.c b/src/settings/nm-settings-connection.c
index 78d2c9b393..2cd2f0d0ae 100644
--- a/src/settings/nm-settings-connection.c
+++ b/src/settings/nm-settings-connection.c
@@ -1563,7 +1563,7 @@ gboolean
 nm_settings_connection_get_timestamp (NMSettingsConnection *connection,
                                       guint64 *out_timestamp)
 {
-	g_return_val_if_fail (NM_IS_SETTINGS_CONNECTION (connection), 0);
+	g_return_val_if_fail (NM_IS_SETTINGS_CONNECTION (connection), FALSE);
 
 	if (out_timestamp)
 		*out_timestamp = NM_SETTINGS_CONNECTION_GET_PRIVATE (connection)->timestamp;
@@ -1591,6 +1591,8 @@ nm_settings_connection_update_timestamp (NMSettingsConnection *connection,
 	gsize len;
 	GError *error = NULL;
 
+	g_return_if_fail (NM_IS_SETTINGS_CONNECTION (connection));
+
 	/* Update timestamp in private storage */
 	priv->timestamp = timestamp;
 	priv->timestamp_set = TRUE;
@@ -1640,6 +1642,8 @@ nm_settings_connection_read_and_fill_timestamp (NMSettingsConnection *connection
 	GError *err = NULL;
 	char *tmp_str;
 
+	g_return_if_fail (NM_IS_SETTINGS_CONNECTION (connection));
+
 	/* Get timestamp from database file */
 	timestamps_file = g_key_file_new ();
 	g_key_file_load_from_file (timestamps_file, SETTINGS_TIMESTAMPS_FILE, G_KEY_FILE_KEEP_COMMENTS, NULL);