Hi Santosh,
Which authentication does not work - dev studio or database?
If it is dev studio -
I see the error is for MXMC_ADMIN user - this is the user used for connection to the databse.You should use the Administrator user instead as described in the documentation.
The Administrator user should exist in the NW User Administration and he should have all the needed roles for IDM - also described in the documentation.
If it is the databse - try to login with the MXMC_ADMIN - have in mind that the prefix is case sensitive. Also check your password - if it enetered correctly in the IDM Data source.
Don't forget - you need 2 data sources for idm 8.0. One for the studio and one for the database.
Regards
Todor