Laravel Google2FA - The GET method is not supported for this route when incorrect OTP is entered

Question

I have implemented a 2FA system using https://github.com/antonioribeiro/google2f, ALONG WITH https://www.digitalocean.com/community/tutorials/how-to-add-googles-two-factor-authentication-to-laravel and it is working really well. But when an incorrect OTP is entered and then a correct OTP password is subsequently entered, I get the "The GET method is not supported for this route. Supported methods: POST" error message.

There is no issue if the OTP is entered correctly on the first attempt Login Authentication

The issue occurs when I attempt to submit the form a second or subsequent time with the correct password

OTP Rejected

I get this error

Error Message

My Route

<?php

use Illuminate\Support\Facades\Route;
  
use App\Http\Controllers\Auth\RegisterController;
use App\Http\Controllers\HomeController;

Route::redirect('/', '/login');
Route::get('/home', function () {
    if (session('status')) {
        return redirect()->route('admin.home')->with('status', session('status'));
    }

   return redirect()->route('admin.home');
});

Route::post('2fa', function () {
    return redirect(URL()->previous());
})->name('2fa')->middleware('2fa');

// Button pressed on Complete QP Code Form
Route::get('complete-registration', 'Auth\RegisterController@completeRegistration');

Auth::routes();

Route::group(['prefix' => 'admin', 'as' => 'admin.', 'namespace' => 'Admin', 'middleware' => ['2fa']], function () {
    Route::get('/', 'HomeController@index')->name('home');
    // Permissions
    Route::delete('permissions/destroy', 'PermissionsController@massDestroy')->name('permissions.massDestroy');
    Route::resource('permissions', 'PermissionsController');

    // Roles
    Route::delete('roles/destroy', 'RolesController@massDestroy')->name('roles.massDestroy');
    Route::resource('roles', 'RolesController');


etc.....

My View:

@extends('layouts.app')
  
@section('content')
<div class="container">
    <div class="row justify-content-center align-items-center " style="height: 70vh;S">
        <div class="col-md-8 col-md-offset-2">
            <div class="panel panel-default">
                <div class="panel-heading font-weight-bold"><h1>Login Authentication</h1></div>
                <hr>
                @if($errors->any())
                    <div class="col-md-12">
                        <div class="alert alert-danger">
                          <strong>{{$errors->first()}}</strong>
                        </div>
                    </div>
                @endif
  
                <div class="panel-body">
                    <form class="form-horizontal" method="POST" action="{{ route('2fa') }}"> 
                        
                        {{ csrf_field() }}
  
                        <div class="form-group">
                            <p>Please enter the  <strong>OTP</strong> generated on your Authenticator App. <br> Ensure you submit the current one as it refreshes every 30 seconds.</p>
                            <label for="one_time_password" class="col-md-4 control-label">One Time Password</label>
  
                            <div class="col-md-6">
                                <input id="one_time_password" <input type="text" inputmode="numeric" class="form-control" name="one_time_password" required autofocus>
                            </div>
                        </div>
  
                        <div class="form-group">
                            <div class="col-md-6 col-md-offset-4 mt-3">
                                <button type="submit" class="btn btn-primary">
                                    Login
                                </button>
                            </div>
                        </div>
                    </form>
                </div>
            </div>
        </div>
    </div>
</div>
@endsection

I have figured out the Controller that is in play

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class HomeController extends Controller
{

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware(['auth', '2fa']);
    }

    public function index()
    {
        return view('home');
    }

    public function reauthenticate(Request $request)
    {
        // get the logged in user
        $user = \Auth::user();

        // initialise the 2FA class
        $google2fa = app('pragmarx.google2fa');

        // generate a new secret key for the user
        $user->google2fa_secret = $google2fa->generateSecretKey();

        // save the user
        $user->save();

        // generate the QR image
        $QR_Image = $google2fa->getQRCodeInline(
            config('app.name'),
            $user->email,
            $user->google2fa_secret
        );

        // Pass the QR barcode image to our view.
        return view('google2fa.register', ['QR_Image' => $QR_Image,
                                            'secret' => $user->google2fa_secret,
                                            'reauthenticating' => true
                                        ]);
    }
}

Answer 1

I figured it out. I am trapping the get 2fa as follows in web.php:

Route::get('/2fa', function () {
return redirect('/') });