403 Forbidden error is received on file upload – Laravel

I’m trying to upload a file in my Laravel 9 application. On the localhost, it works just fine, however, the same action fails when I try it from my application running on an Amazon Linux EC2.

What I know:

• The action does not throw any exceptions, it just receives an HTTP 403 error. (I’ve enabled debug in my .env)
• I’m only receiving this error in places where I’m trying to upload an image. Other controllers work fine.

What I suspect the issue is:

• I believe the issue is with Apache/server configuration. I’ve added a dd() call in the first line of the update() function and it doesn’t even get there. The 403 error is thrown before that. see below.

What I’ve done to troubleshoot:

• Made sure the S3 bucket policy is ok (the same controller works fine on localhost)
• Made sure the file permissions are ok (see screenshot below)
• Made sure the authorize() function inside the request class returns true
• looked at the error logs and don’t see anything relevant in there either.
• Made sure file_uploads = On, upload_max_filesize = 4M and max_file_uploads = 20 inside php.ini

Here is what my controller looks like (the authorize() function inside UpdateContactRequest returns true):

    //https://myapp.com/contacts/1
    //AppHttpControllersContactController
    public function update(UpdateContactRequest $request, Contact $contact)
    {
        dd($request); //This does not get executed. The 403 error happens before reaching this. 

        $contact->update($request->all());

        $this->uploadAvatar($request, $contact);

        Flash::success('Contact updated successfully.');

        return redirect(route('dealers.contacts.index', $contact->dealer->id));
    }

Here is the uploadAvatar function I use to do the upload:

    private function uploadAvatar(Request $request, Contact $contact)
    {
        if ($request->hasFile('avatar')) {
            try {
                $contact
                    ->addMediaFromRequest('avatar')
                    ->sanitizingFileName(function ($fileName) {
                        return strtolower(str_replace(['#', '/', '\', ' '], '-', $fileName));
                })
                ->toMediaCollection('avatars');
            } catch (SpatieMediaLibraryMediaCollectionsExceptionsFileUnacceptableForCollection $e) {
                Flash::error($e->getMessage());
            }
        }
    }

How the routes are defined:

Route::get('/', function () {
    return view('welcome');
});

Route::get('/test', AppHttpControllersTestController::class);
Route::get('/embed-iframe/{uuid}', [AppHttpControllersEmbedController::class, 'iframe']);
Route::get('/embed-js/{uuid}', [AppHttpControllersEmbedController::class, 'js']);
Auth::routes();

Route::middleware('admin')->group(function () {
    Route::get('/home', [AppHttpControllersHomeController::class, 'index'])->name('home');
    Route::resource('dealers', AppHttpControllersDealerController::class);
    Route::post('refreshDealerCRMData', [AppHttpControllersDealerController::class, 'refreshCRMData']);
    Route::post('loadCRMView', [AppHttpControllersDealerController::class, 'loadCRMView']);
    Route::resource('cms', AppHttpControllersCmsController::class);
    Route::resource('crms', AppHttpControllersCrmController::class);
    Route::resource('leads', AppHttpControllersLeadController::class);
    Route::resource('contacts', AppHttpControllersContactController::class);
    Route::resource('attachment-categories', AppHttpControllersAttachmentCategoryController::class);
    Route::resource('CRMAttachments', AppHttpControllersCRMAttachmentController::class);
    Route::resource('dealers.leads', AppHttpControllersDealerLeadController::class)->scoped([
        'dealers' => 'dealer.id',
        'leads' => 'lead.id',
    ]);
    Route::resource('dealers.contacts', AppHttpControllersDealerContactController::class)->scoped([
        'dealers' => 'dealer.id',
        'contacts' => 'contact.id',
    ]);
});

Here is a screenshot of my root directory (/var/www/html):

Here are my virtual hosts defined in /etc/httpd/conf/httpd.conf

<VirtualHost *:443>
 ServerAdmin [email protected]
 ServerName myapp.com
 ServerAlias www.myapp.com
 DocumentRoot /var/www/html/public
 <Directory /var/www/html>
  Options Indexes FollowSymLinks MultiViews
  AllowOverride All
  Require all granted
 </Directory>
</VirtualHost>

<VirtualHost *:80>
  ServerAdmin [email protected]
  ServerName myapp.com
  ServerAlias www.myapp.com
  DocumentRoot /var/www/html/public
  <Directory /var/www/html>
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All
    Require all granted
  </Directory>
</VirtualHost>

Here is my IAM policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:ListBucket",
                "s3:GetObject"
            ],
            "Resource": [
                "arn:aws:s3:::mybucket",
                "arn:aws:s3:::mybucket/*"
            ]
        }
    ]
}

Here is a screenshot of the exact error being thrown:

How can I further troubleshoot this when no actual exception is thrown?