Error in Laravel Accessor while retrieving date in specific format

I am using Laravel accessor to access value of date field in specific format. But, I am getting error from carbon library of InvalidArgument. Below is my code.

<?php

namespace App\modules\hrm;

use App\Helper\DateFormat;
use Illuminate\Database\Eloquent\Model;

class Holiday extends Model
{
    protected $guarded = [];
    protected $dates = ['off_date'];

    public function setOffDateAttribute($date)
    {
        $this->attributes['off_date'] = DateFormat::convertToDBFormat($date);
    }

    public function getOffDateAttribute($date){
        return DateFormat::convertToUIFormat($date);
    }
}

Helper File

<?php


namespace App\Helper;

use Carbon\Carbon;

class DateFormat
{

    public static function convertToDBFormat($date) {
        return Carbon::createFromFormat('d/m/Y', $date)->format('Y-m-d');
    }

    public static function convertToUIFormat($date) {
        return Carbon::createFromFormat('Y-m-d', $date)->format('d/m/Y');
    }
}

?>

I am getting error from Carbon but I think I am doing something wrong while sending those values, maybe i am not using the laravel accessor feature properly.

via Chebli Mohamed