Illegal string offset 'locale' error in Laravel Voyager new user login

I’m using Laravel Voyager for my web app.

When I added a new contributor user and tried to enter his dashboard. I got the “Illegal string offset ‘locale’” error.

Error path: /home/turongro/public_html/vendor/tcg/voyager/src/Models/User.php

Error line:

public function getLocaleAttribute()
{
    return $this->settings['locale'];
}

Before getting this error, I changed 'locale' => 'ru' in config/app.php

#php #laravel