为什么上传云文件存储出现一个VM75998:1 Error: errCode: -1 | errMsg: cloud.uploadFile:fail uploadFile:fail createUploadTask:fail file not found; at cloud.uploadFile api; 地错误

upload:function(){

    wx.chooseImage({

      count: 1,

      sizeType: ['original', 'compressed'],

      sourceType: ['album', 'camera'],

      success(res) {

        const tempFilePaths = res.tempFilePaths

        wx.cloud.uploadFile({

          cloudPath: 'example.png',

          filePath: 'tempFilePaths[0]', // 文件路径

          success: res => {

            // get resource ID

            console.log(res.fileID);

          },

          fail: err => {

            console.error(err);

          }

        })

      }

    })

  }