ORA-12638: Credential retrieval failed

Question

I have a legacy VB6 application which I\'ve inherited. The issue I\'m facing is that I\'m getting the infamous

ORA-12638: Credential retrieval failed
         


        

Answer 1

I installed Oracle Database 11g Express Edition 32-bit on Windows 10 professional 64-bit (spanish edition).

After restart PC all works ok.
But the next day I get error using SQL*PLus and SQLTools 1.9 build 15:

 ORA-12638: Credential retrieval failed

I modified the sqlnet.ora file so:

SQLNET.AUTHENTICATION_SERVICES= (NONE)

and now I can connect using SQLPlus, SQLTools 1.9 build 15.