first upload all files

app/Http/Middleware/CheckForMaintenanceMode.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace FleetCart\Http\Middleware;
+
+use Closure;
+use Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode as BaseCheckForMaintenanceMode;
+
+class CheckForMaintenanceMode extends BaseCheckForMaintenanceMode
+{
+    /**
+     * The URIs that should be accessible while maintenance mode is enabled.
+     *
+     * @var array
+     */
+    protected $except = [
+        '*/admin*',
+    ];
+
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @param  \Closure  $next
+     * @return mixed
+     *
+     * @throws \Symfony\Component\HttpKernel\Exception\HttpException
+     * @throws \Illuminate\Foundation\Http\Exceptions\MaintenanceModeException
+     */
+    public function handle($request, Closure $next)
+    {
+        if (
+            config('app.installed')
+            && $this->app->isDownForMaintenance()
+            && optional(auth()->user())->hasRoleName('Admin')
+        ) {
+            return $next($request);
+        }
+
+        return parent::handle($request, $next);
+    }
+}