ORA-28500: connection from ORACLE to a non-Oracle system returned this message

Experts -

I'm getting the error when I tried to connect from oracle to mysql via DBLINK.

I guess this is something to do with the User/privileges.

Need some help.

ERROR at line 1:
ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[Generic Connectivity Using ODBC]DRV_InitTdp: errors.h (2112): ;
[unixODBC][TCX][MyODBC]Access denied for user 'oracle'@'localhost' (using
password: YES) (SQL State: S1000; SQL Code: 1045)
ORA-02063: preceding 2 lines from MYSQL

tnsping mysql is ok

here is the dblink creation staement..

create database link mysql connect to "username" identified by "passwd"
using '(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = tcp)(HOST = testhost)(PORT = 1523))) (CONNECT_DATA = (SID = mysql)) (HS=OK))' ;