diff --git a/portainer/api.py b/portainer/api.py
index 2f16a61..11ac570 100644
--- a/portainer/api.py
+++ b/portainer/api.py
@@ -1185,7 +1185,7 @@ class PortainerApi:
             self.get_endpoint(endpoint_id)
         if stack is not None:
             for s in stack:
-                self.stack_ids = [self._resolve_stack_id(s, endpoint_id)]
+                self.stack_ids.append(self._resolve_stack_id(s, endpoint_id))
         for stck in self.stack_ids:
             path = f"/stacks/{stck}/start"
             if self.endpoint_id is not None: