diff --git a/sale_stock_operating_unit/models/stock_warehouse.py b/sale_stock_operating_unit/models/stock_warehouse.py
index c4eabcc795..3fe320e312 100644
--- a/sale_stock_operating_unit/models/stock_warehouse.py
+++ b/sale_stock_operating_unit/models/stock_warehouse.py
@@ -14,9 +14,9 @@ class StockWarehouse(models.Model):
     @api.constrains('operating_unit_id')
     def _check_existing_so_in_wh(self):
         for rec in self:
-            sales = self.env['sales.order'].search([
+            sales = self.env['sale.order'].search([
                 ('warehouse_id', '=', rec.id),
-                ('operating_unit_id', '!=', rec.operating_unit_id)])
+                ('operating_unit_id', '!=', rec.operating_unit_id.id)])
             if sales:
                 raise ValidationError(_(
                     'Sales Order records already exist(s) for this warehouse'