login error on linux (mongodb has started )
system: linuxmint 
db: sudo service mongod start  //(has started)
when  I click the button to login:


TypeError: Failed to fetch                       
Uncaught (in promise) TypeError: Cannot read property 'error' of undefined              
    at eval (eval at <anonymous> (app.js:1341), <anonymous>:39:46)

I'm new to vuex ,dont know what caused the err
![_039](https://cloud.githubusercontent.com/assets/10154292/25167041/806c9f0a-2510-11e7-8df1-9d17f668a82b.jpg)
