diff --git a/opencga-server/src/main/java/org/opencb/opencga/server/rest/operations/VariantOperationWebService.java b/opencga-server/src/main/java/org/opencb/opencga/server/rest/operations/VariantOperationWebService.java
index 14fb051c85..4b9613b926 100644
--- a/opencga-server/src/main/java/org/opencb/opencga/server/rest/operations/VariantOperationWebService.java
+++ b/opencga-server/src/main/java/org/opencb/opencga/server/rest/operations/VariantOperationWebService.java
@@ -593,7 +593,12 @@ public Response submitOperationToProject(String toolId, String project, ToolPara
     public Response submitOperation(String toolId, String project, String study, ToolParams params, String jobName, String jobDescription,
                                     String jobDependsOn, String jobTags, String jobScheduledStartTime, String jobPriority, Boolean dryRun) {
         try {
-            Map<String, Object> paramsMap = params.toParams();
+            Map<String, Object> paramsMap;
+            if (params != null) {
+                paramsMap = params.toParams();
+            } else {
+                paramsMap = new HashMap<>();
+            }
             if (StringUtils.isNotEmpty(study)) {
                 paramsMap.put(ParamConstants.STUDY_PARAM, study);
             }