diff --git a/ckanext/datapusher_plus/datastore_utils.py b/ckanext/datapusher_plus/datastore_utils.py
index 8500f47..1851505 100644
--- a/ckanext/datapusher_plus/datastore_utils.py
+++ b/ckanext/datapusher_plus/datastore_utils.py
@@ -25,11 +25,23 @@ def default(self, obj: object) -> object:
         return json.JSONEncoder.default(self, obj)
 
 
+def _site_user_context():
+    """A context that names the site user.
+
+    From CKAN 2.11 the activity plugin requires context["user"] on every
+    action that records an activity (datastore_create and datastore_delete
+    both patch the resource; resource_delete records one too), and raises
+    ValidationError({"user_id": ["User not found"]}) otherwise.
+    """
+    site_user = tk.get_action("get_site_user")({"ignore_auth": True}, {})
+    return {"ignore_auth": True, "user": site_user["name"]}
+
+
 def delete_datastore_resource(resource_id: str) -> None:
     """Delete a resource from datastore."""
     try:
         tk.get_action("datastore_delete")(
-            {"ignore_auth": True}, {"resource_id": resource_id, "force": True}
+            _site_user_context(), {"resource_id": resource_id, "force": True}
         )
     except tk.ObjectNotFound:
         raise utils.JobError("Deleting existing datastore failed.")
@@ -39,7 +51,7 @@ def delete_resource(resource_id: str) -> None:
     """Delete a resource from CKAN."""
     try:
         tk.get_action("resource_delete")(
-            {"ignore_auth": True}, {"id": resource_id, "force": True}
+            _site_user_context(), {"id": resource_id, "force": True}
         )
     except tk.ObjectNotFound:
         raise utils.JobError("Deleting existing resource failed.")
@@ -160,7 +172,7 @@ def send_resource_to_datastore(
         }
     try:
         resource_dict = tk.get_action("datastore_create")(
-            {"ignore_auth": True}, request
+            _site_user_context(), request
         )
         return resource_dict
     except Exception as e: