ORA-12631: Username retrieval failed

Following error occurred when i tried to login my database. Services of Oracle is running. I also restarted the services.

Error:

C:\Users\oracle>sqlplus sys@xe as sysdba
SQL*Plus: Release 11.2.0.2.0 Production on Thu Jan 24 10:58:53 2019
Copyright (c) 1982, 2014, Oracle. All rights reserved.
Enter password:
ERROR:
ORA-12631: Username retrieval failed


Solution:

1. Check the SQLNET file with parameter value

--If parameter has NONE value then convert it into the NTS value & Save the file.
SQLNET.AUTHENTICATION_SERVICES = (NONE)
to
SQLNET.AUTHENTICATION_SERVICES = (NTS)


2. If you are in window environment open the CMD with Administrator rights and try to connect the SQLPLUS / as sysdba

3. Check the REMOTE_LOGIN_PASSWORDFILE parameter.

show parameter remote_login_passwordfile
NAME TYPE VALUE
-------------------------- ------ ------
remote_login_passwordfile string NONE


4. If it using the NONE value then convert it into EXCLUSIVE value, so that it will start using password file.

alter system set remote_login_passwordfile=EXCLUSIVE scope=spfile;


5. Restart the database for parameter change effects

shutdown immediate;
startup;


6. Again change the SQLNET ora file parameter back to NONE value

SQLNET.AUTHENTICATION_SERVICES = (NONE)


7. Now check the connectivity it working fine.

C:\Users\oracle>sqlplus sys as sysdba
SQL*Plus: Release 11.2.0.2.0 Production on Thu Jan 24 11:45:53 2019
Copyright (c) 1982, 2014, Oracle. All rights reserved.
Enter password:
Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production
SQL> exit


8. Hopefully upper steps fixed the issue but if you want more test then tried to create new password file.

orapwd file=D:\oraclexe\oracle\11.2.0\server\database\PWDXE.ora password="sys123" entries=3