1.首先你要确定你的签名可以通过官方校验

https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=20_1

2.当然了，你报这个错说明你微信都调起来了，责任不在后端

3. 贴一个后端常见的返回

{
	"code": 0,
	"message": "操作成功！",
	"data": {
		"timeStamp": "1600596714",
		"package": "Sign=WXPay",
		"paySign": "75F5C70FBF38505C592AE5513D6862F4",
		"appId": "wx80d3035405fc6eb7",
		"signType": "MD5",
		"partnerid": "1568307481",
		"prepayid": "wx20181154284051bb717bf5e1dfbc3e0000",
		"nonceStr": "1600596714319"
	}
}

4.微信官方文档里的说明 https://pay.weixin.qq.com/wiki/doc/api/app/app.php?chapter=8_5

5.这个sign.应该传   signType signType signType signType signType