XDB username and password required
When installing Apex on 12cR2 multitenant this popup appears:
This Popup appears when user : ANONYMOUS status is LOCKED or EXPIRED .
Solution:
Connect as sysdba to CDB$root then alter user account status:
SQL> select account_status from dba_users where username='ANONYMOUS';
ACCOUNT_STATUS
--------------------------------
EXPIRED & LOCKED
SQL> alter user ANONYMOUS ACCOUNT UNLOCK;
SQL> select account_status from dba_users where username='ANONYMOUS';
ACCOUNT_STATUS
--------------------------------
EXPIRED
SQL> alter user ANONYMOUS identified by ANONYMOUS ACCOUNT UNLOCK;
user Altered..
SQL> select account_status from dba_users where username='ANONYMOUS';
ACCOUNT_STATUS
--------------------------------
OPEN
Hope this help..
if you still having troubles then alter the following user
ALTER USER APEX_PUBLIC_USER IDENTIFIED BY APEX_PUBLIC_USER ACCOUNT UNLOCK;
Thank you.