diff --git a/MapControl/Shared/WmtsTileLayer.cs b/MapControl/Shared/WmtsTileLayer.cs
index 3bd1039a..c5db770c 100644
--- a/MapControl/Shared/WmtsTileLayer.cs
+++ b/MapControl/Shared/WmtsTileLayer.cs
@@ -20,7 +20,8 @@ namespace MapControl
     public class WmtsTileLayer : MapTileLayerBase
     {
         public static readonly DependencyProperty CapabilitiesUriProperty = DependencyProperty.Register(
-            nameof(CapabilitiesUri), typeof(Uri), typeof(WmtsTileLayer), new PropertyMetadata(null));
+            nameof(CapabilitiesUri), typeof(Uri), typeof(WmtsTileLayer),
+            new PropertyMetadata(null, (o, e) => ((WmtsTileLayer)o).TileMatrixSet = null));
 
         public static readonly DependencyProperty LayerIdentifierProperty = DependencyProperty.Register(
             nameof(LayerIdentifier), typeof(string), typeof(WmtsTileLayer), new PropertyMetadata(null));
@@ -169,7 +170,7 @@ namespace MapControl
 
         private async void OnLoaded(object sender, RoutedEventArgs e)
         {
-            if (CapabilitiesUri != null)
+            if (TileMatrixSet == null && CapabilitiesUri != null)
             {
                 try
                 {
diff --git a/MapControl/Shared/WmtsTileSource.cs b/MapControl/Shared/WmtsTileSource.cs
index 21606ff6..f0902dd8 100644
--- a/MapControl/Shared/WmtsTileSource.cs
+++ b/MapControl/Shared/WmtsTileSource.cs
@@ -19,17 +19,17 @@ namespace MapControl
 
         public override Uri GetUri(int x, int y, int zoomLevel)
         {
-            if (zoomLevel < 0 || zoomLevel >= tileMatrixes.Count)
+            Uri uri = null;
+
+            if (zoomLevel >= 0 && zoomLevel < tileMatrixes.Count)
             {
-                return null;
+                uri = new Uri(UriFormat
+                    .Replace("{TileMatrix}", tileMatrixes[zoomLevel].Identifier)
+                    .Replace("{TileCol}", x.ToString())
+                    .Replace("{TileRow}", y.ToString()));
             }
 
-            var url = UriFormat
-                .Replace("{TileMatrix}", tileMatrixes[zoomLevel].Identifier)
-                .Replace("{TileCol}", x.ToString())
-                .Replace("{TileRow}", y.ToString());
-
-            return new Uri(url);
+            return uri;
         }
     }
 }