diff --git a/umap/static/umap/js/umap.features.js b/umap/static/umap/js/umap.features.js
index ce17aa0d..f4f51ae2 100644
--- a/umap/static/umap/js/umap.features.js
+++ b/umap/static/umap/js/umap.features.js
@@ -585,7 +585,7 @@ L.U.Marker = L.Marker.extend({
         ];
         var builder = new L.U.FormBuilder(this, coordinatesOptions, {
             callback: function () {
-                if (!this._latlng.isValid()) return;
+                if (!this._latlng.isValid()) return this.map.ui.alert({content: L._('Invalid latitude or longitude'), level: 'error'});
                 this._redraw();
                 this.bringToCenter();
             },