wx.downloadFile 总是报downloadFile:fail createDownloadTask:fail exceed max download connection count 10

wx.downloadFile({

    url: "http://yunjiazheng-static.oss-cn-shanghai.aliyuncs.com/app/lite/app/title@2x.png",

    success: (res) => {

    },

    fail:(err)=>{

        console.log(err)

    },

    complete:()=>{

   }

})