Laravel Sometimes Showing 404 not found page

I'm working on Laravel 8 and i have a problem sometimes when I refresh page or open it direct by link showing

Not found page 404 error , i tried lots of solutions on internet but no solution working with me .

Another note : it's also showing for me when i send request using ajax it's the most time showed for me .

My web.php :

<?php

use App\Http\Middleware\AdminAuth;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/

$adminPathName = env('ADMIN_PATH');

Route::get($adminPathName . '/test/{locale}', function ($locale) {
    session('lang', 'en');

    app()->setLocale($locale);
    echo App::getLocale();
});

Route::get('/', function () {
    return view('frontend.home');
});

$adminPathName = env('ADMIN_PATH');
$userPath = env('USER_PATH');

Route::get($adminPathName . '/login', 'Admin\LoginController@login');
Route::post($adminPathName . '/signin', 'Admin\LoginController@signin');
Route::group(['middleware' => ['AdminAuth']], function () {
    $adminPathName = env('ADMIN_PATH');
    Route::get($adminPathName . '/dashboard', 'Admin\AdminController@home');
    Route::get($adminPathName . '/languages/manage-languages', 'Admin\LanguageController@index');
    Route::post($adminPathName . '/languages/add-language', 'Admin\LanguageController@addLanguage');
    Route::post($adminPathName . '/languages/add-translate', 'Admin\LanguageController@addTranslate');
    Route::post($adminPathName . '/languages/update-translate', 'Admin\LanguageController@updateTranslate');
    Route::post($adminPathName . '/languages/remove-translate', 'Admin\LanguageController@removeTranslate');
    Route::post($adminPathName . '/languages/remove-language', 'Admin\LanguageController@removeLanguage');
    Route::post($adminPathName . '/languages/sync-language', 'Admin\LanguageController@syncLanguage');
    Route::get($adminPathName . '/languages/translate/{langId}', 'Admin\LanguageController@translateById');
});


// todo this route should be added below .
Route::get('/login/facebook/callback', 'User\LoginController@facebookCallback');

Route::group(['prefix' => '/{locale}', 'middleware' => \App\Http\Middleware\SetLocale::class, 'as' => 'locale'], function () {

    $userPath = env('USER_PATH');

    Route::get('/', function () {
        return view('frontend.home');
    });
    Route::get($userPath . '/login', 'User\LoginController@login');
    Route::post($userPath . '/signin', 'User\LoginController@signin');
    Route::get($userPath . '/create-account', 'User\UserController@createAccount');
    Route::post($userPath . '/complete-register', 'User\UserController@completeRegister');

    /* Facebook Login & Register  */

    Route::get($userPath . '/social/facebook/redirect', 'User\LoginController@facebookRedirect');
    /* ./ Facebook Login & Register  */

    /* Google Login & Register  */
    Route::get($userPath . '/social/google/redirect', 'User\LoginController@googleRedirect');
    Route::get($userPath . '/social/google/callback', 'User\LoginController@googleCallback');
    /* ./ Google Login & Register  */

    Route::get('/change-language/{lang}', 'User\WebSiteController@changeLanguage');

    Route::group(['middleware' => ['UserAuth']], function () {
        $userPath = env('USER_PATH');
        Route::get($userPath . '/dashboard', 'User\UserController@dashboard');
        Route::get($userPath . '/update-profile', 'User\UserController@userProfile');
        Route::get($userPath . '/website/create-website', 'User\WebSiteController@newWebsite');
        Route::post($userPath . '/card/upload-gallery', 'User\UserController@uploadGallery');
        Route::get($userPath . '/cards/new-card/{card_lang}', 'User\CardController@newCard');
        Route::get($userPath . '/cards/new-card/{card_lang}/{card_key}', 'User\CardController@newCard');
        Route::post($userPath . '/cards/get-card-gallery', 'User\CardController@getGalleryByCardId');
        Route::post($userPath . '/cards/update-card', 'User\CardController@updateCard');
        Route::post($userPath . '/cards/update-card-logo', 'User\CardController@updateCardLogo');

        Route::get($userPath . '/logout', function () {
            auth('UserAuth')->logout();
            return redirect(ulocale_path('/login'));
        });
    });


});


Route::group(['domain' => '{account}.localhost'], function () {
    Route::get('/{id}/card', 'User\CardController@shoBusinessCardById');
});

And .htaccess file

RewriteEngine On
<IfModule mod_rewrite.c>
 #Session timeout

<IfModule mod_negotiation.c>
    Options -MultiViews
</IfModule>

   Options +FollowSymlinks
   RewriteEngine On

   # Redirect Trailing Slashes...
   RewriteRule ^(.*)/$ /$1 [L,R=301]

RewriteCond %{REQUEST_FILENAME} -d [OR]
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^ ^$1 [N]

RewriteCond %{REQUEST_URI} (\.\w+$) [NC]
RewriteRule ^(.*)$ public/$1

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php


</IfModule>

The most time it's error showing in the below route :

 Route::post($userPath . '/cards/get-card-gallery', 'User\CardController@getGalleryByCardId');

Controller Side getGalleryByCardId :

public function getGalleryByCardId(Request $request)
{
    $imgs = DB::table('card_docs')
        ->where('user_id', usession('user_id'))
        ->where('card_key', $request->card_key)->get();

    return $imgs;
}