沙箱环境，调用统一下单接口后得到prepay_id，

public Map<String, String> fillResponseData(Map<String, String> reqData) throws Exception {
    reqData.put("appid", config.getAppID());
    reqData.put("partnerid", config.getMchID());
    reqData.put("noncestr", WXPayUtil.generateNonceStr());
    reqData.put("package", "Sign=WXPay");
    String timestamp = String.valueOf(new Date ().getTime()/1000);
    reqData.put("timestamp", timestamp);
    reqData.put("sign", WXPayUtil.generateSignature(reqData, config.getKey(), this.signType));
    log.debug ("---fillResponseData={}",reqData);
    return                          

将以上信息返回到APP端，

调用 api.sendReq(req);

Paytivity.this.finish();

报错：appid未关联paySIgnKey？请问是什么问题导致的