Not able to Validation data in Yii2 model

I am not able to validate value in model. I am newbie in this can anyone suggest what am I doing wrong. I am working on REST API with excel file upload and validating single row at a time

Here is my data and load data in model

$data = array(
    'firstName' => 'asdjqkw',
    'lastName' => '',
    'email' => 'ansm@',
    'companyName' => 'ddq',
    'address_1' => '',
    'address_2' => 'aas',
    'country' => '',
    'state' => 'New Brunswick',
    'city' => '87875',
    'zip' => '484527',
);
$model->load($data);
if (!$model->validate()) {
    $validation = $model->errors;
}

And here is my model rules and attribute labels as I defined required, email and maxlength validation in it but still some values is available still it is sending required validation error for that field

public function rules() {
    return [
        [['firstName', 'lastName', 'email', 'companyName', 'address_1', 'country', 'state', 'city', 'zip'], 'required'],
        ['email', 'email'],
        [['firstName', 'lastName', 'email', 'companyName', 'address_1', 'country', 'state', 'city', 'zip'], 'string', 'max' => 250],
    ];
}

public function attributeLabels() {
    return [
        'firstName' => 'First Name',
        'lastName' => 'Last Name',
        'email' => 'Email',
        'companyName' => 'Company Name',
        'address_1' => 'Address 1',
        'country' => 'Country',
        'state' => 'State',
        'city' => 'City',
        'zip' => 'Zip',
    ];
}

And I get validation errors after loading this data

"firstName": [
  "First Name cannot be blank."
],
"lastName": [
  "Last Name cannot be blank."
],
"email": [
  "Email cannot be blank."
],
"companyName": [
  "Company Name cannot be blank."
],
"address_1": [
  "Address 1 cannot be blank."
],
"country": [
  "Country cannot be blank."
],
"state": [
  "State cannot be blank."
],
"city": [
  "City cannot be blank."
],
"zip": [
  "Zip cannot be blank."
]