Validation messages displaying differently between local environment & server

I am using Docker. 
When I run the project on local environment(windows 11), it gives validation error messages as 
The username field is required.
The password field is required.
But the same project on server(Linux) shows error messages as 
validation.required
validation.required
Both are running on PHP 8.3 and this is CI4 project
This is the part of the code that use for form validation.
$rules = [
                'username' => [
                    'rules' => 'required|string|min_length[5]|max_length[30]',
                    'errors' => [
                        'required' => lang('validation.required', ['field' => lang('users.usersInputUsername')]),
                    ],
                ],
                'password' => [
                    'rules' => 'required|min_length[6]',
                    'errors' => [
                        'required' => lang('validation.required', ['field' => lang('users.usersInputPassword')]),
                    ],
                ]

      ];
if($this->validate($rules){
}
Is there anyone who knows why is this occur?