diff --git a/api/controllers/service_api/dataset/document.py b/api/controllers/service_api/dataset/document.py
index d64d9df05..d571b21a0 100644
--- a/api/controllers/service_api/dataset/document.py
+++ b/api/controllers/service_api/dataset/document.py
@@ -211,6 +211,9 @@ class DocumentAddByFileApi(DatasetApiResource):
         if not dataset:
             raise ValueError("Dataset does not exist.")
 
+        if dataset.provider == "external":
+            raise ValueError("External datasets are not supported.")
+
         indexing_technique = args.get("indexing_technique") or dataset.indexing_technique
         if not indexing_technique:
             raise ValueError("indexing_technique is required.")
@@ -301,6 +304,9 @@ class DocumentUpdateByFileApi(DatasetApiResource):
         if not dataset:
             raise ValueError("Dataset does not exist.")
 
+        if dataset.provider == "external":
+            raise ValueError("External datasets are not supported.")
+
         # indexing_technique is already set in dataset since this is an update
         args["indexing_technique"] = dataset.indexing_technique