Smartware not accept my password on My Cloud PR4100

Hello, I try to use WD Smartware with WD My Cloud pr4100 but when it ask to enter the user name and password it not accept it … after I press next it do nothing !!!
also when I try to access my cloud through the local Network … I can access as an admin, then it shows me the Users folder … and it always asks for the user name and passwords but also it never accept any … Only the admin account or the public account
any suggestions ?