API Authentication between 2 Laravel 10 Applications

I have two Laravel 10 applications, called A and B. The user is using application A and needs to authenticate via an API of application B to obtain a token. The problem is that the authentication on the API of B always fails when it is done from A. However, when I test the API of B with Postman, it correctly returns a token.

Here is the controller method from A :

    public function getToken()
    {
        $response = Http::withHeaders([

            'content-type'    => 'application/json; charset=utf-8',
            'accept'          => '*/*',
            'accept-encoding' => 'gzip,deflate',
            'connection'      => 'close'

        ])->post('http_B_address', [ //I removed the address of B because it was not allowed when I wrote this message.

            'email'    => '[email protected]',
            'password' => 'xyz'

        ]);
                
        if ($response->successful()) {

            $data = $response->json();
            dd($data);

        } else {

            $error = $response->body();
            dd($error);
        }
    }

And the code for B that works well when I test with Postman (routes/api.php) :

Route::post('/token', function (Request $request) {

    $request->validate([
        'email'    => 'required|email',
        'password' => 'required',
    ]);

    $user = User::where('email', $request->email)->first();

    if (Auth::attempt(['email' => $request->email, 'password' => $request->password])) { //Always returns false when I use A and returns true when I use Postman

        $token = $user->createToken('API Token')->plainTextToken;

        return response()->json(['token' => $token]);

    } else {

        return response()->json(['message' => 'Unauthorized'], 401);
    }

});

Have I forgotten something in A? Or do you have any suggestions for me? Thank you for your help.