function IsEmail(email) {

  var regex = /^([a-zA-Z0-9_\.\-\+])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;

  return regex.test(email);

}

$rules = [

    'name' => ['required', 'string', 'max:255'],

    'email' => [

        'required',

        'string',

        'email',

        'max:255',

        'unique:users',

        'regex:/^\w+[-\.\w]*@(?!(?:outlook|myemail|yahoo)\.com$)\w+[-\.\w]*?\.\w{2,4}$/'

    ],

    'password' => ['required', 'string', 'min:8', 'confirmed'],

    'mobile_no' => ['required', 'string', 'min:10'],

    'company' => ['required', 'string', 'max:255'],

    'username' => ['required', 'string', 'max:255', 'unique:users'],

];

// Add a custom message for regex validation on email field.

$messages = [

    'email.regex' => 'We do not accept mails with this domain.'

];

​

Validator::make($data, $rules, $messages);