404 Not Found - on Laravel 5.8 when the route already exists - apache

Question

I have a laravel 5.8 project on a hosted site and I recently added JWT Authentication in order to create APIs for mobile applications. Every API I have created is working fine and sending a proper response, except sometimes I am getting a 404 Not Found error even when the route exists in api.php which I'm calling as https://app.mydomain.com/api/apiname.
Here's how my .htaccess file looks as below.
<IfModule mod_rewrite.c>
<IfModule mod_negotiation.c>
Options -MultiViews
</IfModule>
RewriteEngine On
# Redirect Trailing Slashes If Not A Folder...
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ /$1 [L,R=301]
# Handle Front Controller...
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [L]
# Handle Authorization Header
RewriteCond %{HTTP:Authorization} .
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</IfModule>
and my api.php in Routes is as below,
<?php
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;
use App\Http\Controllers\ApiAuthController;
use App\Http\Controllers\ApiSettingsController;
use App\Http\Controllers\ApiManageUsersController;
/*
|--------------------------------------------------------------------------
| API Routes
|--------------------------------------------------------------------------
|
| Here is where you can register API routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| is assigned the "api" middleware group. Enjoy building your API!
|
*/
Route::middleware('auth:api')->get('/user', function (Request $request) {
return $request->user();
});
//api test
Route::get('/my-api-endpoint', function (Request $request) {
return response()->json(['Hello Laravel 7']);
});
//Auth Routes
Route::post('login', 'ApiAuthController#login');
Route::post('logout', 'ApiAuthController#logout');
Route::post('refresh', 'ApiAuthController#refresh');
Route::post('/rest/re_login', 'ApiAuthController#re_login');
Route::GET('/language_json', 'ApiAuthController#language_json');
//Settings Routes
Route::GET('/branding_info', 'ApiSettingsController#branding_info');
Route::POST('/update_branding_info', 'ApiSettingsController#update_branding_info');
Route::GET('/grading_master', 'ApiSettingsController#grading_master');
Route::POST('/grad_cat_active_inactive', 'ApiSettingsController#grad_cat_active_inactive');
Route::GET('/grading_master/view_lessons', 'ApiSettingsController#view_lessons');
Route::POST('/lesson_active_inactive', 'ApiSettingsController#lesson_active_inactive');
Route::GET('/driving_conditions', 'ApiSettingsController#grading_master');
//Manage Users Routes
Route::GET('/Manage_users/{user_type}', 'ApiManageUsersController#Manage_users');
Note: I am using Plesk to access my server.
Please help me out with this situation.
and here's a screenshot of 404 error which I get in postman,
Thanks in advance....