Hi,
See if the following links helps:
http://community.wd.com/t5/WD-My-Cloud/user-not-authorized/m-p/816905/highlight/true#M23675
http://community.wd.com/t5/WD-My-Cloud/SOLVED-Email-links-not-working-and-Network-Password-Needed/m-p/666093/highlight/true#M5633