Laravel Get Method Not Supported Exception (While the form method is already POST) - laravel

Question

I am working on a Laravel project in which I have a form to write styled text, inside the form I used WYSIWYG editor, and the method of the form is POST. Sometimes when I submit the form it gives me (The GET method is not supported for this route. Supported methods: POST). This usually occurs when I give some styling to my text e.g. adding background color or inserting Arabic Characters. but when I insert plain text English words It works as expected and every things ok.
I added the header("Content-Type: text/html;charset=UTF-8"); at the top of index.php file but the result was not changed
Note: the application works in my local xampp server, but when I upload online I get the problem.
Here is form.blade.php (view)
<form method="POST" action="{{action('MainController#Insert')}}" accept-charset="utf-8">
{{csrf_field()}}
#method('post')
<input type="text" name="title" class="form-control" placeholder="Title"/>
<textarea name="details" id="myeditor"></textarea>
<input type="submit" value="Save"/>
</form>
<script>
CKEDITOR.replace('myeditor');
</script>
Here is my web.php (Routes)
Route::get('/', function () { return view('welcome'); });
Route::get('/form','MainController#LoadForm');
Route::post('/save','MainController#Insert');
And the is my controller
public function LoadForm(Request $req){
return view('form');
}
public function Insert(Request $req){
DB::table('notes')->insert(["title"=>$req->title,"details"=>$req->details]);
return redirect()->back()->with(["message"=>"Note Saved Successfully!"]);
}
Where is the problem?

Answer 1

to simplify it
<form method="POST" action="/save" accept-charset="utf-8">
{{csrf_field()}}
<input type="text" name="title" class="form-control" placeholder="Title"/>
<textarea name="details" id="myeditor"></textarea>
<input type="submit" value="Save"/>
</form>