ORA-12638 error after migration

Great, that really helped me out!

I have 2 websites on the same test IIS server. They both access the same Oracle database on another server in a different domain. Same connection string, same user...

On my site A, the Oracle connection worked, while my site B displayed the connection error ORA-12638!

After some careful consideration, I finally understood where the problem was coming from. My site A does not require authentication, while site B does. And for some reason, the website uses the sqlnet.ora file from its client (I still don't understand that) but the fact is that changing the authentication from NTS to NONE in sqlnet.ora as explained above worked (after restarting the server where IIS is located) and I no longer have any errors.

For your information, the path changes depending on the Oracle versions: sqlnet.ora is found in \oracle\product\10.2.0\client_1\NETWORK\ADMIN\

Thank you very much,
it solved my problem.

It's dumb. It doesn't work!

Thank you, it works great.

It's fine with me.

As we say in our country, it's clean
Thank you my brother

It works!
Thank you for your valuable help.

Perfect!
Thank you for the solution Short, Clear, EFFECTIVE!!!

Thank you very much for this response, which also works on Oracle 11!
I indeed fixed the issue with this trick. However, I had installed Oracle on another disk and I had to modify the file located in: D:\app\xx\product\11.2.0\dbhome_2\NETWORK\ADMIN

Thank you for your help.