diff --git a/server/controllers/add_cart.php b/server/controllers/add_cart.php
index 7d2d8287acb696f27e366d04c7c7898d0355540e..554250c032f13b3e0dbccceb473c82a06b07f714 100644
--- a/server/controllers/add_cart.php
+++ b/server/controllers/add_cart.php
@@ -19,7 +19,7 @@
         $stmt->bind_param("sss", $item_id, $cart_username, $item_quantity);
         $result = $stmt->execute();
         if (!$result) {
-            $response = array("success" => "false", "message" => $stmt.error);
+            $response = array("success" => "false", "message" => $stmt->error);
             die ("Error in query execution: " . $stmt->error);
         } else {
             $response = array("success" => "true", "message" => "item has been added");
diff --git a/server/controllers/cartdetail_query.php b/server/controllers/cartdetail_query.php
index 924499d49ed483b9772cb4b56a3f2bd17a015bc4..1dd9f5042915c10661985f84df9b9816e0d2e74b 100644
--- a/server/controllers/cartdetail_query.php
+++ b/server/controllers/cartdetail_query.php
@@ -21,7 +21,7 @@
 
 
         if (!$result) {
-            $response = array("success" => "false", "message" => $stmt.error);
+            $response = array("success" => "false", "message" => $stmt->error);
             die ("Error in query execution: " . $stmt->error);
         } else {
             $response = array("success" => "true", "message" => "showing ".$cart_username."'s cart", "data" => $resultSet->fetch_all(MYSQLI_ASSOC));
diff --git a/server/controllers/sell_item.php b/server/controllers/sell_item.php
index ebec85d36eee3be718f7190ff3efa45a6f86eaff..3186d75163f26e5a334316857e471fe8df541860 100644
--- a/server/controllers/sell_item.php
+++ b/server/controllers/sell_item.php
@@ -35,7 +35,7 @@
         $stmt->bind_param("issssss", $item_id, $name, $picture_path, $description, $price, $quantity, $seller_username);
         $result = $stmt->execute();
         if (!$result) {
-            $response = array("success" => "false", "message" => $stmt.error);
+            $response = array("success" => "false", "message" => $stmt->error);
             die ("Error in query execution: " . $stmt->error);
         } else {
             $response = array("success" => "true", "message" => "item has been added");