Strange problem when using custom authentication schema

Question

Hello,
I'm building a custom authentication system for the application. Basically, I followed the blog post from Martin: http://www.talkapex.com/2009/03/custom-authentication-status.html
However, the authentication seems working fine at the beginning when running the page 101 from Application Builder and log in, but when I log out from the application (redirect back to page 101) and try to log in with the same credentials, it gives error message "Invalid Login Credentials ". Also, when the application is accessed from public (open page 101 directly using another computer), the authentication doesn't work at all.
Furthermore, I checked the table apex_workspace_access_log and found out that it has "AUTH_SUCCESS" even if using the fake credentials and the login failed (I use "apex_util.set_authentication_result (p_code => 3);" when auth function return false).
I couldn't find the cause of the problem, then I created the same custom authentication in apex.oracle.com. The problem doesn't appear anymore. To make sure they are same, I have double checked the custom authentication in both the development environment and the apex.oracle.com.
This is very strange to me and I don't know where to looking for the problem. Could you give me some advice of what may cause this problem. Thanks in advance!

Answer 1

I found the problem myself. The cause is the VPD, the account table has VPD policy applied, which prevented public access.