diff --git a/src/main/java/org/gcube/common/workspacetaskexecutor/dataminer/WorkspaceDataMinerTaskExecutor.java b/src/main/java/org/gcube/common/workspacetaskexecutor/dataminer/WorkspaceDataMinerTaskExecutor.java
index 0d78a25..293f3ca 100644
--- a/src/main/java/org/gcube/common/workspacetaskexecutor/dataminer/WorkspaceDataMinerTaskExecutor.java
+++ b/src/main/java/org/gcube/common/workspacetaskexecutor/dataminer/WorkspaceDataMinerTaskExecutor.java
@@ -28,7 +28,7 @@ import com.fasterxml.jackson.core.type.TypeReference;
  * The Class WorkspaceDataMinerTaskExecutor.
  *
  * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it
- * May 3, 2018
+ * May 4, 2018
  */
 public class WorkspaceDataMinerTaskExecutor implements ExecutableTask<TaskConfiguration, TaskComputation, TaskExecutionStatus>, ExecutableItem<TaskConfiguration>{
 
@@ -111,6 +111,7 @@ public class WorkspaceDataMinerTaskExecutor implements ExecutableTask<TaskConfig
 		Validate.notNull(taskConfiguration, "The "+TaskConfiguration.class.getSimpleName()+" is null");
 		Validate.notNull(taskConfiguration.getWorkspaceItemId(), "The WorkspaceItem Id in the configuration is null");
 		Validate.notNull(taskConfiguration.getTaskId(), "The Task Id in the configuration is null");
+		Validate.notNull(taskConfiguration.getMaskedToken(), "The Token is missing (add it as masked string)");
 	}