关于wx.checkSession(OBJECT)一直失败

if (token) {       wx.checkSession({         success: function(){           console.log('hasSession')           self.getHomeData()         },         fail: function(res){           console.log(res)           console.log('noSession')           self.login();         }       })     } else {       console.log('noToken')       self.login();     }

Object {errMsg: “checkSession:fail session time out, need relogin”}errMsg: “checkSession:fail session time out, need relogin”__proto__: Object

index.js [sm]:63 noSession

每次都是走fail，请问是什么原因