Recently after I configured database on testing machine and configure the forms to run on middle tier on testing machine (all windows environment), I came across the error ORA-12638.

After little bit of brains storming and checking online, I found out that one of the way to solve this error is to disable the Oracle Advanced Security Authentication and let database use the supplied user name and password to authenticate.

It can be disable by updating the sqlnet.ora file with the following entry:

SQLNET.AUTHENTICATION_SERVICES = (NONE)

Note : Default entry in my case was SQLNET.AUTHENTICATION_SERVICES= (NTS)

Guys do check out other method and let me know.

Any way the above method worked for me and I am happy with that at least by Monday morning, my system will be available for testing purpose