diff --git a/app/Http/Controllers/Course/CourseCartController.php b/app/Http/Controllers/Course/CourseCartController.php
index 033fde72..408b418c 100644
--- a/app/Http/Controllers/Course/CourseCartController.php
+++ b/app/Http/Controllers/Course/CourseCartController.php
@@ -27,8 +27,10 @@ class CourseCartController extends Controller
     public function index(Request $request)
     {
         $coupon = null;
-        if ($request->has('coupon')) {
-            $coupon = $this->couponService->getCoupon($request->coupon);
+        $couponCode = $request->input('coupon');
+
+        if (!empty($couponCode)) {
+            $coupon = $this->couponService->getCoupon($couponCode);
 
             if (!$coupon) {
                 return back()->with('error', 'This coupon is not valid.');
diff --git a/app/Services/Course/CourseCouponService.php b/app/Services/Course/CourseCouponService.php
index 21dc8b1d..ee89ef32 100644
--- a/app/Services/Course/CourseCouponService.php
+++ b/app/Services/Course/CourseCouponService.php
@@ -24,8 +24,12 @@ class CourseCouponService
          ->get();
    }
 
-   public function getCoupon(string $code): ?CourseCoupon
+   public function getCoupon(?string $code): ?CourseCoupon
    {
+      if (!$code) {
+         return null;
+      }
+
       return CourseCoupon::where('code', $code)->first();
    }