toptips为什么无法弹出？

<mp-toptips msg="{{errorMsg}}" type="error" show="{{errorMsg}}" delay="2000"></mp-toptips>

wxml代码如上，json文件如下

"usingComponents": {

"mp-uploader": "/components/uploader/uploader",

"mp-cells": "/components/cells/cells",

"mp-cell": "/components/cell/cell",

"mp-toptips": "/components/toptips/toptips"

},

通过console.log errorMsg已经赋值成功，但是界面不弹出提示