yii2.0验证码总是报错 [ 新手入门 ]

模型

public function rules()
{
    return [
        [['user_name','user_pwd','user_repwd','user_email'],'required','message'=>'不能为空'],
        ['user_repwd','compare','compareAttribute'=>'user_pwd','message'=>'两次密码不一致'],
        ['user_email','email','message'=>'邮箱格式不正确'],
        ['add_time','default','value'=>\time()],
        ['verifycode','captcha','captchaAction' => 'user/captcha','message'=>'重新输入验证码'],
    ];
}

echo $form->field($model,'verifycode',[
    'options'=>['tag'=>'li','class'=>'checkcode'],
    'errorOptions'=>['tag'=>'span','style'=>'color:red;'],
    'hintOptions'=>['tag'=>'p'],
    'labelOptions'=>['tag'=>'label'],
    'template'=>"{label}\n{input}\n{error}\n{hint}"
    ])->widget(Captcha::className(), 
    [
    'options'=>['placeholder'=>'验证码'],
    'captchaAction' => 'user/captcha',
    'imageOptions'=>['style'=>'height:36px;width:150px;cursor:pointer','title'=>'点击刷新'],
    'template'=>"{input}\n{image}<span>看不清？<a href=''>换一张</a></span>",
                                                            
]);

客户端yii自带的ajax验证通过, 提交就报验证码错误

怎么弄啊