Change file name so PHP Slim found the class

Source/API/script/Config/ConnectClass.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Config;
+
+use PDOException;
+
+require_once __DIR__ ."/Connection.php";
+
+class ConnectClass{
+
+    private string $dsn;
+    private string $login;
+    private string $password;
+
+    function __construct(){
+        $this->dsn = "mysql:host=".$_ENV["HOST"].";dbname=".$_ENV["DATABASE"].";";
+        $this->login = $_ENV["USER"];
+        $this->password = $_ENV["PASSWORD"];
+    }
+
+    function connect(): int|Connection
+    {
+        try {
+
+            $connection = new Connection($this->dsn,$this->login,$this->password);
+
+        }catch (PDOException){
+            throw new PDOException();
+        }
+        return $connection;
+    }
+
+
+}

Source/API/script/Config/config.php

@@ -1,29 +0,0 @@
-<?php
-
-namespace Config;
-
-use PDOException;
-
-require_once __DIR__ ."/Connection.php";
-
-class ConnectClass{
-
-    function connect(): int|Connection
-    {
-
-        $dsn = "mysql:host=".$_ENV["HOST"].";dbname=".$_ENV["DATABASE"].";";
-        $login = $_ENV["USER"];
-        $password = $_ENV["PASSWORD"];
-
-        try {
-
-            $connection = new Connection($dsn,$login,$password);
-
-        }catch (PDOException){
-            throw new PDOException();
-        }
-        return $connection;
-    }
-
-
-}

Source/API/script/Gateway/GatewayForm.php

@@ -2,17 +2,19 @@
 
 namespace Gateway;
 
+use Config\ConnectClass;
+use Config\Connection;
 use PDO;
 use PDOException;
 
 class GatewayForm
 {
-    private \Config\Connection $connection;
+    private Connection $connection;
 
     public function __construct()
     {
         try{
-            $this->connection = (new \Config\ConnectClass)->connect();
+            $this->connection = (new ConnectClass)->connect();
         }catch(PDOException $e){
             throw new PDOException();
         }