better error in fetch.diff

diff --git a/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/external/ExternalDataSetClientProvider.java b/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/external/ExternalDataSetClientProvider.java
index de98a704cc..f8a542f6bc 100644
--- a/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/external/ExternalDataSetClientProvider.java
+++ b/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/external/ExternalDataSetClientProvider.java
@@ -162,13 +162,28 @@ public class ExternalDataSetClientProvider {
                 if (response.status == HttpResponseCodes.SC_OK) {
                     return register(def, callback, responseText, mimeType);
                 } else {
-                    return notAbleToRetrieveDataSet(def, callback);
+                    var exception = buildExceptionForResponse(responseText, response);
+                    return notAbleToRetrieveDataSet(def, callback, exception);
                 }
 
             }, error -> notAbleToRetrieveDataSet(def, callback));
         }).catch_(e -> notAbleToRetrieveDataSet(def, callback));
     }
 
+    private Throwable buildExceptionForResponse(String responseText, Response response) {
+        var sb = new StringBuffer("The dataset URL is unreachable with status ");
+        sb.append(response.status);
+        sb.append(" - ");
+        sb.append(response.statusText);
+
+        if (responseText != null && !responseText.trim().isEmpty()) {
+            sb.append("\n");
+            sb.append("Response Text: ");
+            sb.append(responseText);
+        }
+        return new RuntimeException(sb.toString());
+    }
+
     private IThenable<Object> register(ExternalDataSetDef def,
                                        final DataSetReadyCallback callback,
                                        final String responseText,
diff --git a/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/services/RuntimeDataSetClientServices.java b/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/services/RuntimeDataSetClientServices.java
index b6c9843083..a5f4345a43 100644
--- a/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/services/RuntimeDataSetClientServices.java
+++ b/packages/dashbuilder/dashbuilder-runtime-parent/dashbuilder-runtime-client/src/main/java/org/dashbuilder/client/services/RuntimeDataSetClientServices.java
@@ -151,7 +151,7 @@ public class RuntimeDataSetClientServices implements DataSetClientServices {
 
                     @Override
                     public boolean onError(ClientRuntimeError error) {
-                        if (loader.isEditor()) {
+                        if (loader.isEditor() || loader.isClient()) {
                             listener.onError(error);
                         } else {
                             DomGlobal.console.debug("Error retrieving dataset from client, trying from backend");